diff --git a/htroot/BlacklistCleaner_p.java b/htroot/BlacklistCleaner_p.java
index 1af2066bd..7d101b96b 100644
--- a/htroot/BlacklistCleaner_p.java
+++ b/htroot/BlacklistCleaner_p.java
@@ -113,8 +113,8 @@ public class BlacklistCleaner_p {
                 prop.put(RESULTS + "blList", blacklistToUse);
                 prop.put(RESULTS + "entries", illegalEntries.size());
                 prop.putHTML(RESULTS + "blEngine", Switchboard.urlBlacklist.getEngineInfo());
-                prop.put(RESULTS + "disabled", (illegalEntries.size() == 0) ? "1" : "0");
-                if (illegalEntries.size() > 0) {
+                prop.put(RESULTS + "disabled", (illegalEntries.isEmpty()) ? "1" : "0");
+                if (!illegalEntries.isEmpty()) {
                     prop.put(RESULTS + DISABLED + "entries", illegalEntries.size());
                     int i = 0;
                     String key;
@@ -148,7 +148,7 @@ public class BlacklistCleaner_p {
         }
         
         if (supported) {
-            if (lists.size() > 0) {
+            if (!lists.isEmpty()) {
                 prop.put("disabled", "0");
                 prop.put(DISABLED + "blacklists", lists.size());
                 int count = 0;
diff --git a/htroot/BlacklistImpExp_p.java b/htroot/BlacklistImpExp_p.java
index 1a61dae32..8f32fadc2 100644
--- a/htroot/BlacklistImpExp_p.java
+++ b/htroot/BlacklistImpExp_p.java
@@ -61,7 +61,7 @@ public class BlacklistImpExp_p {
         prop.putHTML("blacklistEngine", Switchboard.urlBlacklist.getEngineInfo());
 
         // if we have not chosen a blacklist until yet we use the first file
-        if (blacklistToUse == null && dirlist != null && dirlist.size() > 0) {
+        if (blacklistToUse == null && dirlist != null && !dirlist.isEmpty()) {
             blacklistToUse = dirlist.get(0);
         }
 
diff --git a/htroot/Blacklist_p.java b/htroot/Blacklist_p.java
index 46e4a05b8..a6a168383 100644
--- a/htroot/Blacklist_p.java
+++ b/htroot/Blacklist_p.java
@@ -354,7 +354,7 @@ public class Blacklist_p {
         }
 
         // if we have not chosen a blacklist until yet we use the first file
-        if (blacklistToUse == null && dirlist != null && dirlist.size() > 0) {
+        if (blacklistToUse == null && dirlist != null && !dirlist.isEmpty()) {
             blacklistToUse = dirlist.get(0);
         }
 
diff --git a/htroot/ConfigUpdate_p.java b/htroot/ConfigUpdate_p.java
index 30de5d53a..c63a43d6c 100644
--- a/htroot/ConfigUpdate_p.java
+++ b/htroot/ConfigUpdate_p.java
@@ -177,7 +177,7 @@ public class ConfigUpdate_p {
             }
         }
         // latest downloaded release
-        yacyVersion dflt = (downloadedReleases.size() == 0) ? null : downloadedReleases.last();
+        yacyVersion dflt = (downloadedReleases.isEmpty()) ? null : downloadedReleases.last();
         int relcount = 0;
         for(yacyRelease release : downloadedReleases) {
             prop.put("candeploy_downloadedreleases_" + relcount + "_name", ((release.isMainRelease()) ? "main" : "dev") + " " + release.getReleaseNr() + "/" + release.getSvn());
@@ -204,7 +204,7 @@ public class ConfigUpdate_p {
         }
         
         // dev
-        dflt = (releasess.dev.size() == 0) ? null : releasess.dev.last();
+        dflt = (releasess.dev.isEmpty()) ? null : releasess.dev.last();
         final TreeSet<yacyRelease> remoteDevReleases = releasess.dev;
         remoteDevReleases.removeAll(downloadedReleases);
         for(yacyRelease release : remoteDevReleases) {
diff --git a/htroot/IndexControlRWIs_p.java b/htroot/IndexControlRWIs_p.java
index 4422ace8a..b24e2028c 100644
--- a/htroot/IndexControlRWIs_p.java
+++ b/htroot/IndexControlRWIs_p.java
@@ -390,7 +390,7 @@ public class IndexControlRWIs_p {
             URIMetadataRow entry;
             String us;
             long rn = -1;
-            while ((ranked.size() > 0) && ((entry = ranked.takeURL(false, 60000)) != null)) {
+            while (!ranked.isEmpty() && (entry = ranked.takeURL(false, 60000)) != null) {
                 if ((entry == null) || (entry.metadata() == null)) continue;
                 url = entry.metadata().url();
                 if (url == null) continue;
diff --git a/htroot/News.java b/htroot/News.java
index f9b65997b..be6045f39 100644
--- a/htroot/News.java
+++ b/htroot/News.java
@@ -126,7 +126,7 @@ public class News {
                     final Map<String, String> attributeMap = record.attributes();
                     prop.putHTML("table_list_" + i + "_att", attributeMap.toString());
                     int j = 0;
-                    if (attributeMap.size() > 0) {
+                    if (!attributeMap.isEmpty()) {
 	                    for (Entry<String, String> attribute: attributeMap.entrySet()) {
 	                    	prop.put("table_list_" + i + "_attributes_" + j + "_name", attribute.getKey());
 	                    	prop.putHTML("table_list_" + i + "_attributes_" + j + "_value", attribute.getValue());
diff --git a/htroot/Threaddump_p.java b/htroot/Threaddump_p.java
index 40bd1ae79..c3a7bbc3f 100644
--- a/htroot/Threaddump_p.java
+++ b/htroot/Threaddump_p.java
@@ -134,7 +134,7 @@ public class Threaddump_p {
         HashMap<String, Integer> dumps = dumpStatistic(rootPath, traces, plain, stateIn);
         
         // write dumps
-        while (dumps.size() > 0) {
+        while (!dumps.isEmpty()) {
             Entry<String, Integer> e = removeMax(dumps);
             bufferappend(buffer, plain, "Occurrences: " + e.getValue());
             bufferappend(buffer, plain, e.getKey());
diff --git a/htroot/api/feed.java b/htroot/api/feed.java
index 76dc1f20b..227ea6592 100755
--- a/htroot/api/feed.java
+++ b/htroot/api/feed.java
@@ -54,7 +54,7 @@ public class feed {
             
             // read the channel
             feed = RSSFeed.channels(channels[channelIndex]);
-            if ((feed == null) || (feed.size() == 0)) continue channelIteration;
+            if (feed == null || feed.isEmpty()) continue channelIteration;
 
             RSSMessage message = feed.getChannel();
             if (message != null) {
@@ -62,7 +62,7 @@ public class feed {
                 prop.putXML("channel_description", message.getDescription());
                 prop.put("channel_pubDate", message.getPubDate());
             }
-            while ((messageMaxCount > 0) && (feed.size() > 0)) {
+            while (messageMaxCount > 0 && !feed.isEmpty()) {
                 message = feed.pollMessage();
                 if (message == null) continue;
 
diff --git a/htroot/yacy/transferRWI.java b/htroot/yacy/transferRWI.java
index 308047d65..fd2bacca8 100644
--- a/htroot/yacy/transferRWI.java
+++ b/htroot/yacy/transferRWI.java
@@ -212,7 +212,7 @@ public final class transferRWI {
                 unknownURLs.append(",").append(it.next());
             }
             if (unknownURLs.length() > 0) { unknownURLs.delete(0, 1); }
-            if ((wordhashes.size() == 0) || (received == 0)) {
+            if (wordhashes.isEmpty() || received == 0) {
                 sb.getLog().logInfo("Received 0 RWIs from " + otherPeerName + ", processed in " + (System.currentTimeMillis() - startProcess) + " milliseconds, requesting " + unknownURL.size() + " URLs, blocked " + blocked + " RWIs");
             } else {
                 String firstHash = wordhashes.get(0);
diff --git a/htroot/yacysearch.java b/htroot/yacysearch.java
index 8c74602b7..e98ab2345 100644
--- a/htroot/yacysearch.java
+++ b/htroot/yacysearch.java
@@ -377,7 +377,7 @@ public class yacysearch {
 
             // filter out stopwords
             final TreeSet<String> filtered = SetTools.joinConstructive(query[0], Switchboard.stopwords);
-            if (filtered.size() > 0) {
+            if (!filtered.isEmpty()) {
                 SetTools.excludeDestructive(query[0], Switchboard.stopwords);
             }
 
@@ -543,7 +543,7 @@ public class yacysearch {
             
             // find geographic info
             Set<Location> coordinates = LibraryProvider.geoDB.find(originalquerystring);
-            if (coordinates == null || coordinates.size() == 0 || offset > 0) {
+            if (coordinates == null || coordinates.isEmpty() || offset > 0) {
                 prop.put("geoinfo", "0");
             } else {
                 int i = 0;
@@ -628,14 +628,14 @@ public class yacysearch {
             prop.put("eventID", theQuery.id(false)); // for bottomline
             
             // process result of search
-            if (filtered.size() > 0) {
+            if (!filtered.isEmpty()) {
                 prop.put("excluded", "1");
                 prop.putHTML("excluded_stopwords", filtered.toString());
             } else {
                 prop.put("excluded", "0");
             }
 
-            if (prop == null || prop.size() == 0) {
+            if (prop == null || prop.isEmpty()) {
                 if (post == null || post.get("query", post.get("search", "")).length() < 3) {
                     prop.put("num-results", "2"); // no results - at least 3 chars
                 } else {
diff --git a/htroot/yacysearchtrailer.java b/htroot/yacysearchtrailer.java
index e98e03388..b1bc066e6 100644
--- a/htroot/yacysearchtrailer.java
+++ b/htroot/yacysearchtrailer.java
@@ -61,7 +61,7 @@ public class yacysearchtrailer {
         
         // host navigators
         ArrayList<NavigatorEntry> hostNavigator = theSearch.getHostNavigator(10);
-        if (hostNavigator == null || hostNavigator.size() == 0) {
+        if (hostNavigator == null || hostNavigator.isEmpty()) {
         	prop.put("nav-domains", 0);
         } else {
         	prop.put("nav-domains", 1);
@@ -83,7 +83,7 @@ public class yacysearchtrailer {
         
         // author navigators
         ArrayList<NavigatorEntry> authorNavigator = theSearch.getAuthorNavigator(10);
-        if (authorNavigator == null || authorNavigator.size() == 0) {
+        if (authorNavigator == null || authorNavigator.isEmpty()) {
             prop.put("nav-authors", 0);
         } else {
             prop.put("nav-authors", 1);
@@ -107,7 +107,7 @@ public class yacysearchtrailer {
 
         // topics navigator
         ArrayList<NavigatorEntry> topicNavigator = theSearch.getTopicNavigator(10);
-        if (topicNavigator == null || topicNavigator.size() == 0) {
+        if (topicNavigator == null || topicNavigator.isEmpty()) {
             topicNavigator = new ArrayList<NavigatorEntry>(); 
             prop.put("nav-topics", "0");
         } else {
diff --git a/source/de/anomic/crawler/Balancer.java b/source/de/anomic/crawler/Balancer.java
index 6209a0617..277ed5073 100644
--- a/source/de/anomic/crawler/Balancer.java
+++ b/source/de/anomic/crawler/Balancer.java
@@ -194,7 +194,7 @@ public class Balancer {
             while (i.hasNext()) {
                 if (urlHashes.contains(i.next())) i.remove();
             }
-            if (stack.size() == 0) q.remove();
+            if (stack.isEmpty()) q.remove();
         }
        
        return removedCounter;
@@ -214,12 +214,16 @@ public class Balancer {
         return urlFileIndex.size();
     }
     
+    public boolean isEmpty() {
+        return urlFileIndex.isEmpty();
+    }
+    
     private boolean domainStacksNotEmpty() {
         if (domainStacks == null) return false;
         synchronized (domainStacks) {
             final Iterator<LinkedList<String>> i = domainStacks.values().iterator();
             while (i.hasNext()) {
-                if (i.next().size() > 0) return true;
+                if (!i.next().isEmpty()) return true;
             }
         }
         return false;
@@ -275,7 +279,7 @@ public class Balancer {
     }
     
     private String nextFromDelayed() {
-		if (this.delayed.size() == 0) return null;
+		if (this.delayed.isEmpty()) return null;
 		Long first = this.delayed.firstKey();
 		if (first.longValue() < System.currentTimeMillis()) {
 			return this.delayed.remove(first);
@@ -284,7 +288,7 @@ public class Balancer {
     }
     
     private String anyFromDelayed() {
-        if (this.delayed.size() == 0) return null;
+        if (this.delayed.isEmpty()) return null;
         Long first = this.delayed.firstKey();
         return this.delayed.remove(first);
     }
@@ -325,11 +329,11 @@ public class Balancer {
     	Request crawlEntry = null;
     	synchronized (this) {
     	    String failhash = null;
-    		while (this.urlFileIndex.size() > 0) {
+    		while (!this.urlFileIndex.isEmpty()) {
 		    	// first simply take one of the entries in the top list, that should be one without any delay
 		        String nexthash = nextFromDelayed();
 		        //System.out.println("*** nextFromDelayed=" + nexthash);
-		        if (nexthash == null && this.top.size() > 0) {
+		        if (nexthash == null && !this.top.isEmpty()) {
 		            nexthash = top.remove();
 		            //System.out.println("*** top.remove()=" + nexthash);
 		        }
@@ -418,7 +422,7 @@ public class Balancer {
     }
     
     private void filltop(boolean delay, long maximumwaiting, boolean acceptonebest) {
-    	if (this.top.size() > 0) return;
+    	if (!this.top.isEmpty()) return;
     	
     	//System.out.println("*** DEBUG started filltop delay=" + ((delay) ? "true":"false") + ", maximumwaiting=" + maximumwaiting + ", acceptonebest=" + ((acceptonebest) ? "true":"false"));
     	
@@ -438,7 +442,7 @@ public class Balancer {
     		entry = i.next();
     		
     		// clean up empty entries
-    		if (entry.getValue().size() == 0) {
+    		if (entry.getValue().isEmpty()) {
     			i.remove();
     			continue;
     		}
@@ -457,18 +461,18 @@ public class Balancer {
     		}
     		n = entry.getValue().removeFirst();
     		this.top.add(n);
-    		if (entry.getValue().size() == 0) i.remove();
+    		if (entry.getValue().isEmpty()) i.remove();
     	}
     	
     	// if we could not find any entry, then take the best we have seen so far
-    	if (acceptonebest && this.top.size() > 0 && besthash != null) {
+    	if (acceptonebest && !this.top.isEmpty() && besthash != null) {
     		removeHashFromDomainStacks(besthash);
     		this.top.add(besthash);
     	}
     }
     
     private void fillDomainStacks(int maxdomstacksize) throws IOException {
-    	if (this.domainStacks.size() > 0 && System.currentTimeMillis() - lastDomainStackFill < 120000L) return;
+    	if (!this.domainStacks.isEmpty() && System.currentTimeMillis() - lastDomainStackFill < 120000L) return;
     	this.domainStacks.clear();
     	//synchronized (this.delayed) { delayed.clear(); }
     	this.lastDomainStackFill = System.currentTimeMillis();
diff --git a/source/de/anomic/crawler/CrawlProfile.java b/source/de/anomic/crawler/CrawlProfile.java
index cb25ab1a8..8a5268613 100644
--- a/source/de/anomic/crawler/CrawlProfile.java
+++ b/source/de/anomic/crawler/CrawlProfile.java
@@ -501,7 +501,6 @@ public class CrawlProfile {
             } else {
                 // increase counter
                 dp.inc();
-                doms.put(domain, dp);
             }
             domsCache.put(this.mem.get(HANDLE), doms);
         }
diff --git a/source/de/anomic/crawler/CrawlQueues.java b/source/de/anomic/crawler/CrawlQueues.java
index af026bfd3..c028807bc 100644
--- a/source/de/anomic/crawler/CrawlQueues.java
+++ b/source/de/anomic/crawler/CrawlQueues.java
@@ -380,7 +380,7 @@ public class CrawlQueues {
         
         // check if we have an entry in the provider list, otherwise fill the list
         yacySeed seed;
-        if (remoteCrawlProviderHashes.size() == 0) {
+        if (remoteCrawlProviderHashes.isEmpty()) {
             if (sb.peers != null && sb.peers.sizeConnected() > 0) {
                 final Iterator<yacySeed> e = PeerSelection.getProvidesRemoteCrawlURLs(sb.peers);
                 while (e.hasNext()) {
@@ -391,12 +391,12 @@ public class CrawlQueues {
                 }
             }
         }
-        if (remoteCrawlProviderHashes.size() == 0) return false;
+        if (remoteCrawlProviderHashes.isEmpty()) return false;
         
         // take one entry from the provider list and load the entries from the remote peer
         seed = null;
         String hash = null;
-        while ((seed == null) && (remoteCrawlProviderHashes.size() > 0)) {
+        while ((seed == null) && (!remoteCrawlProviderHashes.isEmpty())) {
             hash = remoteCrawlProviderHashes.remove(remoteCrawlProviderHashes.size() - 1);
             if (hash == null) continue;
             seed = sb.peers.get(hash);
@@ -411,7 +411,7 @@ public class CrawlQueues {
         
         // we know a peer which should provide remote crawl entries. load them now.
         final RSSFeed feed = yacyClient.queryRemoteCrawlURLs(sb.peers, seed, 30, 60000);
-        if (feed == null || feed.size() == 0) {
+        if (feed == null || feed.isEmpty()) {
             // something is wrong with this provider. To prevent that we get not stuck with this peer
             // we remove it from the peer list
             sb.peers.peerActions.peerDeparture(seed, "no results from provided remote crawls");
diff --git a/source/de/anomic/crawler/CrawlStacker.java b/source/de/anomic/crawler/CrawlStacker.java
index 6db4c2a8f..61c68a172 100644
--- a/source/de/anomic/crawler/CrawlStacker.java
+++ b/source/de/anomic/crawler/CrawlStacker.java
@@ -82,6 +82,11 @@ public final class CrawlStacker {
     public int size() {
         return this.fastQueue.queueSize() + this.slowQueue.queueSize();
     }
+    public boolean isEmpty() {
+        if (!this.fastQueue.queueIsEmpty()) return false;
+        if (!this.slowQueue.queueIsEmpty()) return false;
+        return true;
+    }
 
     public void clear() {
         this.fastQueue.clear();
diff --git a/source/de/anomic/crawler/ExternalIndexImporter.java b/source/de/anomic/crawler/ExternalIndexImporter.java
index 1f1cb2133..c59245d7f 100644
--- a/source/de/anomic/crawler/ExternalIndexImporter.java
+++ b/source/de/anomic/crawler/ExternalIndexImporter.java
@@ -170,7 +170,7 @@ public class ExternalIndexImporter extends AbstractImporter implements Importer
                     if (isAborted()) break;
                     
                     // importing entity container to home db
-                    if (newContainer.size() > 0) { homeWordIndex.termIndex().add(newContainer); }
+                    if (!newContainer.isEmpty()) { homeWordIndex.termIndex().add(newContainer); }
                     
                     // delete complete index entity file
                     this.importWordIndex.termIndex().delete(this.wordHash);                 
diff --git a/source/de/anomic/crawler/NoticedURL.java b/source/de/anomic/crawler/NoticedURL.java
index 537736acb..5f077c94e 100755
--- a/source/de/anomic/crawler/NoticedURL.java
+++ b/source/de/anomic/crawler/NoticedURL.java
@@ -121,6 +121,14 @@ public class NoticedURL {
         return ((coreStack == null) ? 0 : coreStack.size()) + ((limitStack == null) ? 0 : limitStack.size()) + ((remoteStack == null) ? 0 : remoteStack.size());
     }
 
+    public boolean isEmpty() {
+        if (coreStack == null) return true;
+        if (!coreStack.isEmpty()) return false;
+        if (!limitStack.isEmpty()) return false;
+        if (!remoteStack.isEmpty()) return false;
+        return true;
+    }
+    
     public int stackSize(final int stackType) {
         switch (stackType) {
             case STACK_TYPE_CORE:     return (coreStack == null) ? 0 : coreStack.size();
diff --git a/source/de/anomic/crawler/RobotsEntry.java b/source/de/anomic/crawler/RobotsEntry.java
index c30bcd431..421fe8d20 100644
--- a/source/de/anomic/crawler/RobotsEntry.java
+++ b/source/de/anomic/crawler/RobotsEntry.java
@@ -187,7 +187,7 @@ public class RobotsEntry {
     }
     
     public boolean isDisallowed(String path) {
-        if ((this.mem == null) || (this.denyPathList.size() == 0)) return false;   
+        if ((this.mem == null) || (this.denyPathList.isEmpty())) return false;   
         
         // if the path is null or empty we set it to /
         if ((path == null) || (path.length() == 0)) path = "/";            
diff --git a/source/de/anomic/data/DidYouMean.java b/source/de/anomic/data/DidYouMean.java
index f855d7ed3..6734e4c86 100644
--- a/source/de/anomic/data/DidYouMean.java
+++ b/source/de/anomic/data/DidYouMean.java
@@ -73,7 +73,7 @@ public class DidYouMean {
 	 */
 	public String getSuggestion(final String word, long timeout) {
 	    Set<String> s = getSuggestions(word, timeout);
-	    if (s == null || s.size() == 0) return null;
+	    if (s == null || s.isEmpty()) return null;
 	    return s.iterator().next();
 	}
 	
@@ -85,7 +85,7 @@ public class DidYouMean {
      */
     public String getSuggestion(final String word, long timeout, int preSortSelection) {
         Set<String> s = getSuggestions(word, timeout, preSortSelection);
-        if (s == null || s.size() == 0) return null;
+        if (s == null || s.isEmpty()) return null;
         return s.iterator().next();
     }
 	
@@ -133,7 +133,7 @@ public class DidYouMean {
         SortedSet<String> result = new TreeSet<String>();
         StringBuilder sb;
         for (int i = 0; i < words.length; i++) {
-            if (s[i].size() == 0) continue;
+            if (s[i].isEmpty()) continue;
             sb = new StringBuilder(20);
             for (int j = 0; j < words.length; j++) {
                 if (j > 0) sb.append(' ');
diff --git a/source/de/anomic/data/MimeTable.java b/source/de/anomic/data/MimeTable.java
index 10350eeb3..c3a76911f 100644
--- a/source/de/anomic/data/MimeTable.java
+++ b/source/de/anomic/data/MimeTable.java
@@ -12,7 +12,7 @@ public class MimeTable {
     private static final Properties mimeTable = new Properties();
     
     public static void init(File mimeFile) {
-        if (mimeTable.size() == 0) {
+        if (mimeTable.isEmpty()) {
             // load the mime table
             BufferedInputStream mimeTableInputStream = null;
             try {
@@ -30,6 +30,10 @@ public class MimeTable {
         return mimeTable.size();
     }
     
+    public static boolean isEmpty() {
+        return mimeTable.isEmpty();
+    }
+    
     public static String ext2mime(String ext) {
         return mimeTable.getProperty(ext, "application/" + ext);
     }
diff --git a/source/de/anomic/data/listManager.java b/source/de/anomic/data/listManager.java
index e97cdf297..c77af1872 100644
--- a/source/de/anomic/data/listManager.java
+++ b/source/de/anomic/data/listManager.java
@@ -71,7 +71,7 @@ public class listManager {
     public static void removeFromListSet(final String setName, final String listName) {
         final Set<String> listSet = getListSet(setName);
         
-        if (listSet.size() > 0) {
+        if (!listSet.isEmpty()) {
             listSet.remove(listName);
             switchboard.setConfig(setName, collection2string(listSet));
         }
@@ -127,7 +127,7 @@ public class listManager {
     public static String collection2string(final Collection<String> col){
         final StringBuilder str = new StringBuilder();
         
-        if (col != null && (col.size() > 0)) {
+        if (col != null && !col.isEmpty()) {
             final Iterator<String> it = col.iterator();
             str.append(it.next());
             while(it.hasNext()) {
diff --git a/source/de/anomic/http/server/HTTPDFileHandler.java b/source/de/anomic/http/server/HTTPDFileHandler.java
index 8942d2cb7..c5d255760 100644
--- a/source/de/anomic/http/server/HTTPDFileHandler.java
+++ b/source/de/anomic/http/server/HTTPDFileHandler.java
@@ -142,7 +142,7 @@ public final class HTTPDFileHandler {
         if (switchboard == null) {
             switchboard = theSwitchboard;
 
-            if (MimeTable.size() == 0) {
+            if (MimeTable.isEmpty()) {
                 // load the mime table
                 final String mimeTablePath = theSwitchboard.getConfig("mimeTable","");
                 Log.logConfig("HTTPDFiles", "Loading mime mapping file " + mimeTablePath);
@@ -174,7 +174,7 @@ public final class HTTPDFileHandler {
                 if (!(htTemplatePath.exists())) htTemplatePath.mkdir();
             }
             //This is now handles by #%env/templates/foo%#
-            //if (templates.size() == 0) templates.putAll(httpTemplate.loadTemplates(htTemplatePath));
+            //if (templates.isEmpty()) templates.putAll(httpTemplate.loadTemplates(htTemplatePath));
             
             // create htLocaleDefault, htLocalePath
             if (htDefaultPath == null) htDefaultPath = theSwitchboard.getConfigPath("htDefaultPath", "htroot");
diff --git a/source/de/anomic/http/server/HTTPDProxyHandler.java b/source/de/anomic/http/server/HTTPDProxyHandler.java
index 3857d1fc8..c0acce0ca 100644
--- a/source/de/anomic/http/server/HTTPDProxyHandler.java
+++ b/source/de/anomic/http/server/HTTPDProxyHandler.java
@@ -485,7 +485,7 @@ public final class HTTPDProxyHandler {
 
                 final ResponseHeader responseHeader = res.getResponseHeader();
                 // determine if it's an internal error of the httpc
-                if (responseHeader.size() == 0) {
+                if (responseHeader.isEmpty()) {
                     throw new Exception(res.getStatusLine());
                 }
 
@@ -570,7 +570,7 @@ public final class HTTPDProxyHandler {
                         FileUtils.copy(res.getDataAsStream(), toClientAndMemory);
                         // cached bytes
                         byte[] cacheArray;
-                        if(byteStream.size() > 0) {
+                        if (byteStream.size() > 0) {
                             cacheArray = byteStream.toByteArray();
                         } else {
                             cacheArray = null;
@@ -821,7 +821,7 @@ public final class HTTPDProxyHandler {
             
             // determine if it's an internal error of the httpc
             final ResponseHeader responseHeader = res.getResponseHeader();
-            if (responseHeader.size() == 0) {
+            if (responseHeader.isEmpty()) {
                 throw new Exception(res.getStatusLine());
             }            
             
@@ -937,7 +937,7 @@ public final class HTTPDProxyHandler {
             
             final ResponseHeader responseHeader = res.getResponseHeader();
             // determine if it's an internal error of the httpc
-            if (responseHeader.size() == 0) {
+            if (responseHeader.isEmpty()) {
                 throw new Exception(res.getStatusLine());
             }                                  
             
diff --git a/source/de/anomic/http/server/HTTPDemon.java b/source/de/anomic/http/server/HTTPDemon.java
index 166db7030..a8cbc55ce 100644
--- a/source/de/anomic/http/server/HTTPDemon.java
+++ b/source/de/anomic/http/server/HTTPDemon.java
@@ -1167,9 +1167,9 @@ public final class HTTPDemon implements serverHandler, Cloneable {
             switch (errorcase) {
                 case ERRORCASE_FILE:
                     tp.put("errorMessageType_file", (detailedErrorMsgFile == null) ? "" : detailedErrorMsgFile.toString());
-                    if ((detailedErrorMsgValues != null) && (detailedErrorMsgValues.size() > 0)) {
+                    if ((detailedErrorMsgValues != null) && !detailedErrorMsgValues.isEmpty()) {
                         // rewriting the value-names and add the proper name prefix:
-                        for(Entry<String, String> entry: detailedErrorMsgValues.entrySet()) {
+                        for (Entry<String, String> entry: detailedErrorMsgValues.entrySet()) {
                             tp.put("errorMessageType_" + entry.getKey(), entry.getValue());
                         }                        
                     }                    
diff --git a/source/de/anomic/search/MediaSnippet.java b/source/de/anomic/search/MediaSnippet.java
index 04aa0b388..734bf9158 100644
--- a/source/de/anomic/search/MediaSnippet.java
+++ b/source/de/anomic/search/MediaSnippet.java
@@ -109,7 +109,7 @@ public class MediaSnippet implements Comparable<MediaSnippet>, Comparator<MediaS
     }
     
     public static ArrayList<MediaSnippet> retrieveMediaSnippets(final DigestURI url, final TreeSet<byte[]> queryhashes, final ContentDomain mediatype, final boolean fetchOnline, final int timeout, final boolean reindexing) {
-        if (queryhashes.size() == 0) {
+        if (queryhashes.isEmpty()) {
             Log.logFine("snippet fetch", "no query hashes given for url " + url);
             return new ArrayList<MediaSnippet>();
         }
@@ -194,12 +194,12 @@ public class MediaSnippet implements Comparable<MediaSnippet>, Comparator<MediaS
             url = entry.getKey();
             desc = entry.getValue();
             s = removeAppearanceHashes(url.toNormalform(false, false), queryhashes);
-            if (s.size() == 0) {
+            if (isEmpty()) {
                 result += "<br /><a href=\"" + url + "\">" + ((desc.length() == 0) ? url : desc) + "</a>";
                 continue;
             }
             s = removeAppearanceHashes(desc, s);
-            if (s.size() == 0) {
+            if (isEmpty()) {
                 result += "<br /><a href=\"" + url + "\">" + ((desc.length() == 0) ? url : desc) + "</a>";
                 continue;
             }
diff --git a/source/de/anomic/search/RankingProcess.java b/source/de/anomic/search/RankingProcess.java
index 8d7bb944a..4d72ef06b 100644
--- a/source/de/anomic/search/RankingProcess.java
+++ b/source/de/anomic/search/RankingProcess.java
@@ -131,7 +131,7 @@ public final class RankingProcess extends Thread {
             this.localSearchInclusion = search.inclusion();
             final ReferenceContainer<WordReference> index = search.joined();
             MemoryTracker.update("SEARCH", new ProfilingGraph.searchEvent(query.id(true), SearchEvent.JOIN, index.size(), System.currentTimeMillis() - timer), false);
-            if (index.size() == 0) {
+            if (index.isEmpty()) {
                 return;
             }
             
@@ -147,7 +147,7 @@ public final class RankingProcess extends Thread {
         // attention: if minEntries is too high, this method will not terminate within the maxTime
 
         assert (index != null);
-        if (index.size() == 0) return;
+        if (index.isEmpty()) return;
         if (local) {
             this.local_resourceSize += fullResource;
         } else {
@@ -306,7 +306,7 @@ public final class RankingProcess extends Thread {
         // returns from the current RWI list the best entry and removes this entry from the list
         SortStack<WordReferenceVars> m;
         SortStack<WordReferenceVars>.stackElement rwi;
-        while (stack.size() > 0) {
+        while (!stack.isEmpty()) {
             rwi = stack.pop();
             if (rwi == null) continue; // in case that a synchronization problem occurred just go lazy over it
             if (!skipDoubleDom) return rwi;
@@ -336,7 +336,7 @@ public final class RankingProcess extends Thread {
                     break; // not the best solution...
                 }
                 if (m == null) continue;
-                if (m.size() == 0) continue;
+                if (m.isEmpty()) continue;
                 if (bestEntry == null) {
                     bestEntry = m.top();
                     continue;
@@ -461,6 +461,14 @@ public final class RankingProcess extends Thread {
         return c;
     }
     
+    public boolean isEmpty() {
+        if (!stack.isEmpty()) return false;
+        for (SortStack<WordReferenceVars> s: this.doubleDomCache.values()) {
+            if (!s.isEmpty()) return false;
+        }
+        return true;
+    }
+    
     public int[] flagCount() {
     	return flagcount;
     }
@@ -705,3 +713,12 @@ public final class RankingProcess extends Thread {
     }
 
 }
+/*
+Thread= Thread-937 id=4224 BLOCKED
+Thread= Thread-919 id=4206 BLOCKED
+Thread= Thread-936 id=4223 BLOCKED
+at net.yacy.kelondro.util.SortStack.pop(SortStack.java:118)
+at de.anomic.search.RankingProcess.takeRWI(RankingProcess.java:310)
+at de.anomic.search.RankingProcess.takeURL(RankingProcess.java:371)
+at de.anomic.search.ResultFetcher$Worker.run(ResultFetcher.java:161)
+*/
diff --git a/source/de/anomic/search/ReferenceOrder.java b/source/de/anomic/search/ReferenceOrder.java
index 9b499bed0..341190afe 100644
--- a/source/de/anomic/search/ReferenceOrder.java
+++ b/source/de/anomic/search/ReferenceOrder.java
@@ -107,7 +107,7 @@ public class ReferenceOrder {
                     entry = di.next();
                     doms.addScore(entry.getKey(), (entry.getValue()).intValue());
                 }
-                if (doms.size() > 0) maxdomcount = doms.getMaxScore();
+                if (!doms.isEmpty()) maxdomcount = doms.getMaxScore();
             } catch (InterruptedException e) {
                 Log.logException(e);
             } catch (Exception e) {
diff --git a/source/de/anomic/search/ResultEntry.java b/source/de/anomic/search/ResultEntry.java
index ebc59e522..95f8a5bf5 100644
--- a/source/de/anomic/search/ResultEntry.java
+++ b/source/de/anomic/search/ResultEntry.java
@@ -161,7 +161,7 @@ public class ResultEntry implements Comparable<ResultEntry>, Comparator<ResultEn
         return (this.textSnippet != null) && (this.textSnippet.getErrorCode() < 11);
     }
     public boolean hasMediaSnippets() {
-        return (this.mediaSnippets != null) && (this.mediaSnippets.size() > 0);
+        return (this.mediaSnippets != null) && (!this.mediaSnippets.isEmpty());
     }
     public String resource() {
         // generate transport resource
diff --git a/source/de/anomic/search/ResultFetcher.java b/source/de/anomic/search/ResultFetcher.java
index cad90cd7c..9b7eb813b 100644
--- a/source/de/anomic/search/ResultFetcher.java
+++ b/source/de/anomic/search/ResultFetcher.java
@@ -88,7 +88,7 @@ public class ResultFetcher {
         // only with the query minus the stopwords which had not been used for the search
         final TreeSet<byte[]> filtered = SetTools.joinConstructive(query.queryHashes, Switchboard.stopwordHashes);
         this.snippetFetchWordHashes = (TreeSet<byte[]>) query.queryHashes.clone();
-        if ((filtered != null) && (filtered.size() > 0)) {
+        if (filtered != null && !filtered.isEmpty()) {
             SetTools.excludeDestructive(this.snippetFetchWordHashes, Switchboard.stopwordHashes);
         }
         
@@ -241,7 +241,7 @@ public class ResultFetcher {
             final long snippetComputationTime = System.currentTimeMillis() - startTime;
             Log.logInfo("SEARCH_EVENT", "media snippet load time for " + metadata.url() + ": " + snippetComputationTime);
             
-            if ((mediaSnippets != null) && (mediaSnippets.size() > 0)) {
+            if (mediaSnippets != null && !mediaSnippets.isEmpty()) {
                 // found media snippets, return entry
                 return new ResultEntry(page, query.getSegment(), peers, null, mediaSnippets, dbRetrievalTime, snippetComputationTime);
             } else if (snippetMode == 1) {
diff --git a/source/de/anomic/search/SearchEvent.java b/source/de/anomic/search/SearchEvent.java
index eb1c86e88..971294cd9 100644
--- a/source/de/anomic/search/SearchEvent.java
+++ b/source/de/anomic/search/SearchEvent.java
@@ -114,7 +114,7 @@ public final class SearchEvent {
             // start global searches
             final long timer = System.currentTimeMillis();
             Log.logFine("SEARCH_EVENT", "STARTING " + fetchpeers + " THREADS TO CATCH EACH " + query.displayResults() + " URLs");
-            this.primarySearchThreads = (query.queryHashes.size() == 0) ? null : yacySearch.primaryRemoteSearches(
+            this.primarySearchThreads = (query.queryHashes.isEmpty()) ? null : yacySearch.primaryRemoteSearches(
                     QueryParams.hashSet2hashString(query.queryHashes),
                     QueryParams.hashSet2hashString(query.excludeHashes),
                     "",
diff --git a/source/de/anomic/search/SearchEventCache.java b/source/de/anomic/search/SearchEventCache.java
index e3ae76287..a567f0c22 100644
--- a/source/de/anomic/search/SearchEventCache.java
+++ b/source/de/anomic/search/SearchEventCache.java
@@ -73,7 +73,7 @@ public class SearchEventCache {
         
         String id = query.id(false);
         SearchEvent event = SearchEventCache.lastEvents.get(id);
-        if (Switchboard.getSwitchboard() != null && Switchboard.getSwitchboard().crawlQueues.noticeURL.size() > 0 && event != null && System.currentTimeMillis() - event.getEventTime() > 60000) {
+        if (Switchboard.getSwitchboard() != null && !Switchboard.getSwitchboard().crawlQueues.noticeURL.isEmpty() && event != null && System.currentTimeMillis() - event.getEventTime() > 60000) {
             // if a local crawl is ongoing, don't use the result from the cache to use possibly more results that come from the current crawl
             // to prevent that this happens during a person switches between the different result pages, a re-search happens no more than
             // once a minute
diff --git a/source/de/anomic/search/Segment.java b/source/de/anomic/search/Segment.java
index e0952a8a8..1f67b5f13 100644
--- a/source/de/anomic/search/Segment.java
+++ b/source/de/anomic/search/Segment.java
@@ -468,7 +468,7 @@ public class Segment {
                             }
                         }
                     }
-                    if (urlHashs.size() > 0) try {
+                    if (!urlHashs.isEmpty()) try {
                         final int removed = termIndex.remove(container.getTermHash(), urlHashs);
                         Log.logFine("INDEXCLEANER", container.getTermHashAsString() + ": " + removed + " of " + container.size() + " URL-entries deleted");
                         lastWordHash = container.getTermHash();
diff --git a/source/de/anomic/search/Switchboard.java b/source/de/anomic/search/Switchboard.java
index e0432952f..e4c4cbadf 100644
--- a/source/de/anomic/search/Switchboard.java
+++ b/source/de/anomic/search/Switchboard.java
@@ -433,7 +433,7 @@ public final class Switchboard extends serverSwitch {
         listManager.reloadBlacklists();
 
         // load badwords (to filter the topwords)
-        if (badwords == null || badwords.size() == 0) {
+        if (badwords == null || badwords.isEmpty()) {
             final File badwordsFile = new File(rootPath, SwitchboardConstants.LIST_BADWORDS_DEFAULT);
             badwords = SetTools.loadList(badwordsFile, NaturalOrder.naturalComparator);
             badwordHashes = Word.words2hashes(badwords);
@@ -443,7 +443,7 @@ public final class Switchboard extends serverSwitch {
         }
 
         // load stopwords
-        if (stopwords == null || stopwords.size() == 0) {
+        if (stopwords == null || stopwords.isEmpty()) {
             final File stopwordsFile = new File(rootPath, SwitchboardConstants.LIST_STOPWORDS_DEFAULT);
             stopwords = SetTools.loadList(stopwordsFile, NaturalOrder.naturalComparator);
             stopwordHashes = Word.words2hashes(stopwords);
@@ -1092,7 +1092,7 @@ public final class Switchboard extends serverSwitch {
             crawlQueues.coreCrawlJobSize() > 0 ||
             crawlQueues.limitCrawlJobSize() > 0 ||
             crawlQueues.remoteTriggeredCrawlJobSize() > 0 ||
-            (crawlStacker != null && crawlStacker.size() > 0) ||
+            (crawlStacker != null && !crawlStacker.isEmpty()) ||
             crawlQueues.noticeURL.notEmpty())
             return false;
         return this.crawler.cleanProfiles();
diff --git a/source/de/anomic/search/TextSnippet.java b/source/de/anomic/search/TextSnippet.java
index 01ce68b0e..1201243ad 100644
--- a/source/de/anomic/search/TextSnippet.java
+++ b/source/de/anomic/search/TextSnippet.java
@@ -197,7 +197,7 @@ public class TextSnippet implements Comparable<TextSnippet>, Comparator<TextSnip
     }
     public String getLineMarked(final TreeSet<byte[]> queryHashes) {
         if (line == null) return "";
-        if ((queryHashes == null) || (queryHashes.size() == 0)) return line.trim();
+        if ((queryHashes == null) || (queryHashes.isEmpty())) return line.trim();
         if (line.endsWith(".")) line = line.substring(0, line.length() - 1);
         final Iterator<byte[]> i = queryHashes.iterator();
         byte[] h;
@@ -310,7 +310,7 @@ public class TextSnippet implements Comparable<TextSnippet>, Comparator<TextSnip
     public static TextSnippet retrieveTextSnippet(final URIMetadataRow.Components comp, final TreeSet<byte[]> queryhashes, final boolean fetchOnline, final boolean pre, final int snippetMaxLength, final int maxDocLen, final boolean reindexing) {
         // heise = "0OQUNU3JSs05"
         final DigestURI url = comp.url();
-        if (queryhashes.size() == 0) {
+        if (queryhashes.isEmpty()) {
             //System.out.println("found no queryhashes for URL retrieve " + url);
             return new TextSnippet(url, null, ERROR_NO_HASH_GIVEN, queryhashes, "no query hashes given");
         }
@@ -427,7 +427,7 @@ public class TextSnippet implements Comparable<TextSnippet>, Comparator<TextSnip
         //if (hrefline  != null) line += (line.length() == 0) ? hrefline  : "<br />" + hrefline;
         if (textline  != null) line += (line.length() == 0) ? textline  : "<br />" + textline;
         
-        if ((line == null) || (remainingHashes.size() > 0)) return new TextSnippet(url, null, ERROR_NO_MATCH, remainingHashes, "no matching snippet found",resFavicon);
+        if (line == null || !remainingHashes.isEmpty()) return new TextSnippet(url, null, ERROR_NO_MATCH, remainingHashes, "no matching snippet found",resFavicon);
         if (line.length() > snippetMaxLength) line = line.substring(0, snippetMaxLength);
 
         // finally store this snippet in our own cache
@@ -451,7 +451,7 @@ public class TextSnippet implements Comparable<TextSnippet>, Comparator<TextSnip
             computeTextSnippet(final Iterator<StringBuilder> sentences, final TreeSet<byte[]> queryhashes, int maxLength) {
         try {
             if (sentences == null) return null;
-            if ((queryhashes == null) || (queryhashes.size() == 0)) return null;
+            if ((queryhashes == null) || (queryhashes.isEmpty())) return null;
             Iterator<byte[]> j;
             TreeMap<byte[], Integer> hs;
             StringBuilder sentence;
@@ -471,14 +471,14 @@ public class TextSnippet implements Comparable<TextSnippet>, Comparator<TextSnip
             
             String result;
             TreeSet<byte[]> remaininghashes;
-            while (os.size() > 0) {
+            while (!os.isEmpty()) {
                 sentence = os.remove(os.lastKey()); // sentence with the biggest score
                 Object[] tsr = computeTextSnippet(sentence.toString(), queryhashes, maxLength);
                 if (tsr == null) continue;
                 result = (String) tsr[0];
                 if ((result != null) && (result.length() > 0)) {
                     remaininghashes = (TreeSet<byte[]>) tsr[1];
-                    if (remaininghashes.size() == 0) {
+                    if (remaininghashes.isEmpty()) {
                         // we have found the snippet
                         return new Object[]{result, remaininghashes};
                     } else if (remaininghashes.size() < queryhashes.size()) {
@@ -510,7 +510,7 @@ public class TextSnippet implements Comparable<TextSnippet>, Comparator<TextSnip
             computeTextSnippet(String sentence, final TreeSet<byte[]> queryhashes, final int maxLength) {
         try {
             if (sentence == null) return null;
-            if ((queryhashes == null) || (queryhashes.size() == 0)) return null;
+            if ((queryhashes == null) || (queryhashes.isEmpty())) return null;
             byte[] hash;
             
             // find all hashes that appear in the sentence
diff --git a/source/de/anomic/server/serverAccessTracker.java b/source/de/anomic/server/serverAccessTracker.java
index 8097dcd54..2cc447bf0 100644
--- a/source/de/anomic/server/serverAccessTracker.java
+++ b/source/de/anomic/server/serverAccessTracker.java
@@ -58,7 +58,7 @@ public class serverAccessTracker {
         SortedMap<Long, String> track;
         while (i.hasNext()) {
             track = i.next().getValue();
-            if (track.tailMap(Long.valueOf(System.currentTimeMillis() - maxTrackingTime)).size() == 0) {
+            if (track.tailMap(Long.valueOf(System.currentTimeMillis() - maxTrackingTime)).isEmpty()) {
                 // all entries are too old. delete the whole track
                 i.remove();
             } else {
@@ -116,7 +116,7 @@ public class serverAccessTracker {
         synchronized (access) {
             if ((access = clearTooOldAccess(access)).size() != access.size()) {
                 // write back to tracker
-                if (access.size() == 0) {
+                if (access.isEmpty()) {
                     accessTracker.remove(host);
                 } else {
                     accessTracker.put(host, access);
diff --git a/source/de/anomic/tools/disorderHeap.java b/source/de/anomic/tools/disorderHeap.java
index 8f5c386c2..7615426e2 100644
--- a/source/de/anomic/tools/disorderHeap.java
+++ b/source/de/anomic/tools/disorderHeap.java
@@ -50,7 +50,7 @@ public class disorderHeap implements Serializable {
     }
 
     public synchronized String remove() {
-        if (list.size() == 0) return null;
+        if (list.isEmpty()) return null;
         final int pos = (int) ((System.currentTimeMillis() / 13) % list.size());
         return list.remove(pos);
     }
@@ -69,6 +69,9 @@ public class disorderHeap implements Serializable {
         return list.size();
     }
 
+    public synchronized boolean isEmpty() {
+        return list.isEmpty();
+    }
 
     public static void main(final String[] args) {
         final disorderHeap ul = new disorderHeap();
diff --git a/source/de/anomic/tools/disorderSet.java b/source/de/anomic/tools/disorderSet.java
index 8af16cb79..b5e028d34 100644
--- a/source/de/anomic/tools/disorderSet.java
+++ b/source/de/anomic/tools/disorderSet.java
@@ -28,7 +28,7 @@ import java.util.Set;
 public class disorderSet extends HashSet<String> implements Set<String> {
 
     private static final long serialVersionUID = 1L;
-    disorderHeap dh;
+    private disorderHeap dh;
 
     public disorderSet() {
         super();
@@ -36,13 +36,13 @@ public class disorderSet extends HashSet<String> implements Set<String> {
     }
 
     public boolean hasAny() {
-        return (this.size() > 0);
+        return !this.isEmpty();
     }
 
     public String any() {
         // return just any element
-        if ((dh == null) || (dh.size() == 0)) {
-            if (this.size() == 0) return null;
+        if (dh == null || dh.isEmpty()) {
+            if (this.isEmpty()) return null;
             // fill up the queue
             dh = new disorderHeap();
             final Iterator<String> elements = this.iterator();
diff --git a/source/de/anomic/tools/enumerateFiles.java b/source/de/anomic/tools/enumerateFiles.java
index 4833d5353..1c5f45c84 100644
--- a/source/de/anomic/tools/enumerateFiles.java
+++ b/source/de/anomic/tools/enumerateFiles.java
@@ -65,14 +65,14 @@ public class enumerateFiles implements Enumeration<File> {
         do {
             // System.out.println("D " + hierarchy.toString());
             t = null;
-            while ((t == null) && (hierarchy.size() > 0)) {
+            while ((t == null) && (!hierarchy.isEmpty())) {
                 t = hierarchy.get(hierarchy.size() - 1);
-                if (t.size() == 0) {
+                if (t.isEmpty()) {
                     hierarchy.remove(hierarchy.size() - 1); // we step up one hierarchy
                     t = null;
                 }
             }
-            if ((hierarchy.size() == 0) || (t == null || t.size() == 0)) return null; // this is the end
+            if (hierarchy.isEmpty() || (t == null || t.isEmpty())) return null; // this is the end
             // fetch value
             if (incOrder) f = t.first(); else f = t.last();
             t.remove(f);
diff --git a/source/de/anomic/tools/loaderCore.java b/source/de/anomic/tools/loaderCore.java
index f0d1c7a00..f86e93bfd 100644
--- a/source/de/anomic/tools/loaderCore.java
+++ b/source/de/anomic/tools/loaderCore.java
@@ -68,7 +68,7 @@ public abstract class loaderCore implements loaderProcess {
     public boolean available() {
         // true if it is ok to feed with feed()
         return (status() == STATUS_READY) ||
-               ((status() == STATUS_COMPLETED) && ((result == null) || (result.size() == 0)));
+               (status() == STATUS_COMPLETED && (result == null || result.isEmpty()));
     }
     
     public Exception error() {
diff --git a/source/de/anomic/tools/nxTools.java b/source/de/anomic/tools/nxTools.java
index b9dc6391a..5b7881bc5 100644
--- a/source/de/anomic/tools/nxTools.java
+++ b/source/de/anomic/tools/nxTools.java
@@ -91,14 +91,14 @@ public class nxTools {
         }    
 
     public static String tail1(final Vector<String> list) {
-    	if ((list == null) || (list.size() == 0)) return "";
+    	if (list == null || list.isEmpty()) return "";
     	return list.lastElement();
     }
     
     public static String tail1(final ArrayList<String> list) {
-        if ((list == null) || (list.size() == 0)) return "";
+        if (list == null || list.isEmpty()) return "";
         return list.get(list.size()-1);
-        }
+    }
 
     public static String awk(String sentence, final String separator, int count) {
 	// returns the nth word of sentence, where count is the counter and the first word has the number 1
diff --git a/source/de/anomic/yacy/dht/Dispatcher.java b/source/de/anomic/yacy/dht/Dispatcher.java
index 9999cbd82..cc9e26dc0 100755
--- a/source/de/anomic/yacy/dht/Dispatcher.java
+++ b/source/de/anomic/yacy/dht/Dispatcher.java
@@ -154,7 +154,7 @@ public class Dispatcher {
         ArrayList<ReferenceContainer<WordReference>> containers = selectContainers(hash, limitHash, maxContainerCount, maxReferenceCount, maxtime, false);
 
         // if ram does not provide any result, take from file
-        //if (containers.size() == 0) containers = selectContainers(hash, limitHash, maxContainerCount, maxtime, false);
+        //if (containers.isEmpty()) containers = selectContainers(hash, limitHash, maxContainerCount, maxtime, false);
         return containers;
     }
     
@@ -180,11 +180,11 @@ public class Dispatcher {
                 (indexContainerIterator.hasNext()) &&
                 (System.currentTimeMillis() < timeout) &&
                 ((container = indexContainerIterator.next()) != null) &&
-                ((containers.size() == 0) ||
+                ((containers.isEmpty()) ||
                  (Base64Order.enhancedCoder.compare(container.getTermHash(), limitHash) < 0))
                 
         ) {
-            if (container.size() == 0) continue;
+            if (container.isEmpty()) continue;
             refcount += container.size();
             containers.add(container);
         }
@@ -201,7 +201,7 @@ public class Dispatcher {
                     urlHashes.add(it.next().metadataHash());
                 }
                 if (this.log.isFine()) this.log.logFine("selected " + urlHashes.size() + " urls for word '" + c.getTermHashAsString() + "'");
-                if (urlHashes.size() > 0) this.segment.termIndex().remove(c.getTermHash(), urlHashes);
+                if (!urlHashes.isEmpty()) this.segment.termIndex().remove(c.getTermHash(), urlHashes);
             }
             rc = containers;
         } else {
@@ -321,7 +321,7 @@ public class Dispatcher {
     	ArrayList<ReferenceContainer<WordReference>> selectedContainerCache = selectContainers(hash, limitHash, maxContainerCount, maxReferenceCount, maxtime);
         this.log.logInfo("selectContainersToCache: selectedContainerCache was filled with " + selectedContainerCache.size() + " entries");
         
-        if (selectedContainerCache == null || selectedContainerCache.size() == 0) {
+        if (selectedContainerCache == null || selectedContainerCache.isEmpty()) {
         	this.log.logInfo("splitContainersFromCache: selectedContainerCache is empty, cannot do anything here.");
         	return false;
         }
diff --git a/source/de/anomic/yacy/dht/Transmission.java b/source/de/anomic/yacy/dht/Transmission.java
index dfe91f848..20a099969 100644
--- a/source/de/anomic/yacy/dht/Transmission.java
+++ b/source/de/anomic/yacy/dht/Transmission.java
@@ -184,7 +184,7 @@ public class Transmission {
         }
         
         public boolean transmit() {
-            if (this.targets.size() == 0) return false;
+            if (this.targets.isEmpty()) return false;
             yacySeed target = this.targets.remove(0);
             // transferring selected words to remote peer
             if (target == seeds.mySeed() || target.hash.equals(seeds.mySeed().hash)) {
diff --git a/source/de/anomic/yacy/graphics/WebStructureGraph.java b/source/de/anomic/yacy/graphics/WebStructureGraph.java
index 0da5c688f..aa3d9d2e4 100644
--- a/source/de/anomic/yacy/graphics/WebStructureGraph.java
+++ b/source/de/anomic/yacy/graphics/WebStructureGraph.java
@@ -257,7 +257,7 @@ public class WebStructureGraph {
                 }
             }
         }
-        if (h.size() == 0) return null;
+        if (h.isEmpty()) return null;
         return new structureEntry(domhash, domain, date, h);
     }
     
diff --git a/source/de/anomic/yacy/yacyClient.java b/source/de/anomic/yacy/yacyClient.java
index a5221f6d3..a5b57d760 100644
--- a/source/de/anomic/yacy/yacyClient.java
+++ b/source/de/anomic/yacy/yacyClient.java
@@ -319,7 +319,7 @@ public final class yacyClient {
             final byte[] content = postToFile(target, "query.html", post, 10000);
             final HashMap<String, String> result = FileUtils.table(content);
             
-            if (result == null || result.size() == 0) { return null; }
+            if (result == null || result.isEmpty()) { return null; }
             //final Date remoteTime = yacyCore.parseUniversalDate((String) result.get(yacySeed.MYTIME)); // read remote time
             return yacySeed.genRemoteSeed(result.get("response"), salt, false);
         } catch (final Exception e) {
@@ -341,7 +341,7 @@ public final class yacyClient {
             final byte[] content = postToFile(target, "query.html", post, 5000);
             final HashMap<String, String> result = FileUtils.table(content);
             
-            if (result == null || result.size() == 0) { return -1; }
+            if (result == null || result.isEmpty()) { return -1; }
             return Integer.parseInt(result.get("response"));
         } catch (final Exception e) {
             yacyCore.log.logSevere("yacyClient.queryRWICount error:" + e.getMessage());
@@ -364,7 +364,7 @@ public final class yacyClient {
             final byte[] content = postToFile(target, "query.html", post, 5000);
             final HashMap<String, String> result = FileUtils.table(content);
             
-            if ((result == null) || (result.size() == 0)) return -1;
+            if (result == null || result.isEmpty()) return -1;
             final String resp = result.get("response");
             if (resp == null) {
                 return -1;
@@ -493,7 +493,7 @@ public final class yacyClient {
             return null;
         }
 
-        if ((result == null) || (result.size() == 0)) {
+        if (result == null || result.isEmpty()) {
             if (yacyCore.log.isFine()) yacyCore.log.logFine("SEARCH failed FROM "
 					+ target.hash
 					+ ":"
diff --git a/source/de/anomic/yacy/yacyCore.java b/source/de/anomic/yacy/yacyCore.java
index d065cdec9..c90239353 100644
--- a/source/de/anomic/yacy/yacyCore.java
+++ b/source/de/anomic/yacy/yacyCore.java
@@ -338,7 +338,7 @@ public class yacyCore {
                 seeds = PeerSelection.seedsByAge(sb.peers, false, attempts); // best for seed list maintenance/cleaning
             }
 
-            if ((seeds == null) || seeds.size() == 0) { return 0; }
+            if (seeds == null || seeds.isEmpty()) { return 0; }
             if (seeds.size() < attempts) { attempts = seeds.size(); }
 
             // This will try to get Peers that are not currently in amIAccessibleDB
diff --git a/source/de/anomic/yacy/yacyNewsPool.java b/source/de/anomic/yacy/yacyNewsPool.java
index 8ea29dd6b..9e4e1b762 100644
--- a/source/de/anomic/yacy/yacyNewsPool.java
+++ b/source/de/anomic/yacy/yacyNewsPool.java
@@ -308,7 +308,7 @@ public class yacyNewsPool {
     
     public yacyNewsRecord myPublication() throws IOException {
         // generate a record for next peer-ping
-        if (outgoingNews.size() == 0) return null;
+        if (outgoingNews.isEmpty()) return null;
         final yacyNewsRecord record = outgoingNews.topInc();
         if ((record != null) && (record.distributed() >= maxDistribution)) {
             // move record to its final position. This is only for history
diff --git a/source/de/anomic/yacy/yacyNewsQueue.java b/source/de/anomic/yacy/yacyNewsQueue.java
index c81356ec8..810aa718b 100644
--- a/source/de/anomic/yacy/yacyNewsQueue.java
+++ b/source/de/anomic/yacy/yacyNewsQueue.java
@@ -99,23 +99,27 @@ public class yacyNewsQueue {
     public int size() {
         return queueStack.size();
     }
+    
+    public boolean isEmpty() {
+        return queueStack.isEmpty();
+    }
 
     public synchronized void push(final yacyNewsRecord entry) throws IOException {
         queueStack.push(r2b(entry, true));
     }
 
     public synchronized yacyNewsRecord pop() throws IOException {
-        if (queueStack.size() == 0) return null;
+        if (queueStack.isEmpty()) return null;
         return b2r(queueStack.pop());
     }
 
     public synchronized yacyNewsRecord top() throws IOException {
-        if (queueStack.size() == 0) return null;
+        if (queueStack.isEmpty()) return null;
         return b2r(queueStack.top());
     }
 
     public synchronized yacyNewsRecord topInc() throws IOException {
-        if (queueStack.size() == 0) return null;
+        if (queueStack.isEmpty()) return null;
         final yacyNewsRecord entry = pop();
         if (entry != null) {
             entry.incDistribution();
diff --git a/source/de/anomic/yacy/yacyRelease.java b/source/de/anomic/yacy/yacyRelease.java
index 072d39bd4..77c051a72 100644
--- a/source/de/anomic/yacy/yacyRelease.java
+++ b/source/de/anomic/yacy/yacyRelease.java
@@ -127,8 +127,8 @@ public final class yacyRelease extends yacyVersion {
         
         // check if we know that there is a release that is more recent than that which we are using
         final DevAndMainVersions releases = yacyRelease.allReleases(true, sb.getConfig("update.onlySignedFiles", "1").equals("1"));
-        final yacyRelease latestmain = (releases.main.size() == 0) ? null : releases.main.last();
-        final yacyRelease latestdev  = (releases.dev.size() == 0) ? null : releases.dev.last();
+        final yacyRelease latestmain = (releases.main.isEmpty()) ? null : releases.main.last();
+        final yacyRelease latestdev  = (releases.dev.isEmpty()) ? null : releases.dev.last();
         final String concept = sb.getConfig("update.concept", "any");
         String blacklist = sb.getConfig("update.blacklist", "...[123]");
         if (blacklist.equals("....[123]")) {
@@ -213,10 +213,10 @@ public final class yacyRelease extends yacyVersion {
         DevAndMainVersions locLatestRelease = latestReleases.get(location);
         if (force ||
             (locLatestRelease == null) /*||
-            ((latestRelease[0].size() == 0) &&
-             (latestRelease[1].size() == 0) &&
-             (latestRelease[2].size() == 0) &&
-             (latestRelease[3].size() == 0) )*/) {
+            ((latestRelease[0].isEmpty()) &&
+             (latestRelease[1].isEmpty()) &&
+             (latestRelease[2].isEmpty()) &&
+             (latestRelease[3].isEmpty()) )*/) {
             locLatestRelease = allReleaseFrom(location);
             latestReleases.put(location, locLatestRelease);
         }
@@ -607,7 +607,7 @@ public final class yacyRelease extends yacyVersion {
         }
         
         // if we have some files
-        if(downloadedreleases.size() > 0) {
+        if (!downloadedreleases.isEmpty()) {
             Log.logFine("STARTUP", "deleting downloaded releases older than "+ deleteAfterDays +" days");
             
             // keep latest version
diff --git a/source/de/anomic/yacy/yacySeed.java b/source/de/anomic/yacy/yacySeed.java
index c76dc2c9f..6eba6d00d 100644
--- a/source/de/anomic/yacy/yacySeed.java
+++ b/source/de/anomic/yacy/yacySeed.java
@@ -677,7 +677,7 @@ public class yacySeed implements Cloneable {
         // take one gap; prefer biggest but take also another smaller by chance
         String interval = null;
         final Random r = new Random();
-        while (gaps.size() > 0) {
+        while (!gaps.isEmpty()) {
             interval = gaps.remove(gaps.lastKey());
             if (r.nextBoolean()) break;
         }
diff --git a/source/de/anomic/yacy/yacySeedDB.java b/source/de/anomic/yacy/yacySeedDB.java
index 5ec6f5825..1db61ee9f 100644
--- a/source/de/anomic/yacy/yacySeedDB.java
+++ b/source/de/anomic/yacy/yacySeedDB.java
@@ -215,7 +215,7 @@ public final class yacySeedDB implements AlternativeDomainNames {
     }
     
     public synchronized void removeMySeed() {
-        if ((seedActiveDB.size() == 0) && (seedPassiveDB.size() == 0) && (seedPotentialDB.size() == 0)) return; // avoid that the own seed is initialized too early
+        if (seedActiveDB.isEmpty() && seedPassiveDB.isEmpty() && seedPotentialDB.isEmpty()) return; // avoid that the own seed is initialized too early
         if (this.mySeed == null) initMySeed();
         try {
             seedActiveDB.remove(mySeed.hash);
diff --git a/source/net/yacy/dbtest.java b/source/net/yacy/dbtest.java
index c7d1c5a45..342710ea9 100644
--- a/source/net/yacy/dbtest.java
+++ b/source/net/yacy/dbtest.java
@@ -436,7 +436,7 @@ public class dbtest {
                     for (int j = 0; j < readCount; j++) {
                         InstantBusyThread.oneTimeJob(new ReadJob(table_test, table_reference, random.nextLong() % writeCount), random.nextLong() % 1000, 20);
                     }
-                    if ((ra.size() > 0) && (random.nextLong() % 7 == 0)) {
+                    if (!ra.isEmpty() && random.nextLong() % 7 == 0) {
                         rc++;
                         p = Math.abs(random.nextInt() % ra.size());
                         R = ra.get(p);
@@ -477,7 +477,7 @@ public class dbtest {
                     for (int j = 0; j < readCount; j++) {
                         new ReadJob(table_test, table_reference, random.nextLong() % writeCount).run();
                     }
-                    if ((ra.size() > 0) && (random.nextLong() % 7 == 0)) {
+                    if (!ra.isEmpty() && random.nextLong() % 7 == 0) {
                         rc++;
                         p = Math.abs(random.nextInt() % ra.size());
                         R = ra.get(p);
diff --git a/source/net/yacy/document/Condenser.java b/source/net/yacy/document/Condenser.java
index a59c73552..9eb892c11 100644
--- a/source/net/yacy/document/Condenser.java
+++ b/source/net/yacy/document/Condenser.java
@@ -117,10 +117,10 @@ public final class Condenser {
         this.RESULT_FLAGS = new Bitfield(4);
 
         // construct flag set for document
-        if (document.getImages().size() > 0) RESULT_FLAGS.set(flag_cat_hasimage, true);
-        if (document.getAudiolinks().size() > 0) RESULT_FLAGS.set(flag_cat_hasaudio, true);
-        if (document.getVideolinks().size() > 0) RESULT_FLAGS.set(flag_cat_hasvideo, true);
-        if (document.getApplinks().size()   > 0) RESULT_FLAGS.set(flag_cat_hasapp,   true);
+        if (!document.getImages().isEmpty())     RESULT_FLAGS.set(flag_cat_hasimage, true);
+        if (!document.getAudiolinks().isEmpty()) RESULT_FLAGS.set(flag_cat_hasaudio, true);
+        if (!document.getVideolinks().isEmpty()) RESULT_FLAGS.set(flag_cat_hasvideo, true);
+        if (!document.getApplinks().isEmpty())   RESULT_FLAGS.set(flag_cat_hasapp,   true);
         
         this.languageIdentificator = new Identificator();
         
@@ -566,7 +566,7 @@ public final class Condenser {
                 sIndex = 0;
                 s.clear();
             }
-            while (s.size() == 0) {
+            while (s.isEmpty()) {
                 if (!e.hasNext()) return null;
                 r = e.next();
                 if (r == null) return null;
diff --git a/source/net/yacy/document/Document.java b/source/net/yacy/document/Document.java
index c5fedc7f6..8444d6765 100644
--- a/source/net/yacy/document/Document.java
+++ b/source/net/yacy/document/Document.java
@@ -152,7 +152,7 @@ public class Document {
      */
     public String dc_language() {
         if (this.languages == null) return null;
-        if (this.languages.size() == 0) return null;
+        if (this.languages.isEmpty()) return null;
         if (this.languages.size() == 1) return languages.iterator().next();
         if (this.languages.contains(this.source.language())) return this.source.language();
         // now we are confused: the declared languages differ all from the TLD
@@ -203,7 +203,7 @@ dc_rights
             s = (this.keywords.get(i)).trim();
             if (s.length() > 0) hs.add(s.toLowerCase());
         }
-        if (hs.size() == 0) return "";
+        if (hs.isEmpty()) return "";
         // generate a new list
         final StringBuilder sb = new StringBuilder(this.keywords.size() * 6);
         final Iterator<String> i = hs.iterator();
diff --git a/source/net/yacy/document/TextParser.java b/source/net/yacy/document/TextParser.java
index 721a67ed7..8c3b06dc1 100644
--- a/source/net/yacy/document/TextParser.java
+++ b/source/net/yacy/document/TextParser.java
@@ -212,7 +212,7 @@ public final class TextParser {
         final String documentCharset = htmlParser.patchCharsetEncoding(charset);
         List<Idiom> idioms = idiomParser(location, mimeType);
         
-        if (idioms.size() == 0) {
+        if (idioms.isEmpty()) {
             final String errorMsg = "No parser available to parse extension '" + location.getFileExtension() + "' or mimetype '" + mimeType + "'";
             log.logInfo("Unable to parse '" + location + "'. " + errorMsg);
             throw new ParserException(errorMsg, location);
@@ -249,7 +249,7 @@ public final class TextParser {
         try {
             // try to get a parser. If this works, we don't need the parser itself, we just return null to show that everything is ok.
             List<Idiom> idioms = idiomParser(url, mimeType);
-            return (idioms == null || idioms.size() == 0) ? "no parser found" : null;
+            return (idioms == null || idioms.isEmpty()) ? "no parser found" : null;
         } catch (ParserException e) {
             // in case that a parser is not available, return a error string describing the problem.
             return e.getMessage();
diff --git a/source/net/yacy/document/language/Identificator.java b/source/net/yacy/document/language/Identificator.java
index dddb6517f..e7fef8c43 100644
--- a/source/net/yacy/document/language/Identificator.java
+++ b/source/net/yacy/document/language/Identificator.java
@@ -130,7 +130,7 @@ public final class Identificator {
             }
         }
         
-        if (relevantLanguages.size() == 0) return null;
+        if (relevantLanguages.isEmpty()) return null;
            
         // compare characters in text with characters in statistics
         final float[] offsetList = new float[relevantLanguages.size()];
diff --git a/source/net/yacy/document/parser/csvParser.java b/source/net/yacy/document/parser/csvParser.java
index 57208dea9..8e8598195 100644
--- a/source/net/yacy/document/parser/csvParser.java
+++ b/source/net/yacy/document/parser/csvParser.java
@@ -78,7 +78,7 @@ public class csvParser extends AbstractParser implements Idiom {
         // the first row is used as headline
         // all lines are artificially terminated by a '.' to separate them as sentence for the condenser.
         List<String[]> table = getTable(location, mimeType, charset, source);
-        if (table.size() == 0) throw new ParserException("document has no lines", location);
+        if (table.isEmpty()) throw new ParserException("document has no lines", location);
         StringBuilder sb = new StringBuilder();
         for (String[] row: table) sb.append(concatRow(row)).append(' ');
         try {
diff --git a/source/net/yacy/document/parser/html/ContentScraper.java b/source/net/yacy/document/parser/html/ContentScraper.java
index e0fe109d1..2d5e6faf3 100644
--- a/source/net/yacy/document/parser/html/ContentScraper.java
+++ b/source/net/yacy/document/parser/html/ContentScraper.java
@@ -290,7 +290,7 @@ public class ContentScraper extends AbstractScraper implements Scraper {
         
         // otherwise take any headline
         for (int i = 0; i < 4; i++) {
-            if (headlines[i].size() > 0) return headlines[i].get(0);
+            if (!headlines[i].isEmpty()) return headlines[i].get(0);
         }
         
         // take description tag
@@ -393,7 +393,7 @@ public class ContentScraper extends AbstractScraper implements Scraper {
             if (p > 0) cl[i] = cl[i].substring(0, p);
             if (ISO639.exists(cl[i])) hs.add(cl[i]);
         }
-        if (hs.size() == 0) return null;
+        if (hs.isEmpty()) return null;
         return hs;
     }
     
diff --git a/source/net/yacy/document/parser/html/ContentTransformer.java b/source/net/yacy/document/parser/html/ContentTransformer.java
index c8720c8f4..c2d1979e4 100644
--- a/source/net/yacy/document/parser/html/ContentTransformer.java
+++ b/source/net/yacy/document/parser/html/ContentTransformer.java
@@ -77,13 +77,13 @@ public class ContentTransformer extends AbstractTransformer implements Transform
                     r.close();
                 } catch (final IOException e) {
                 }
-                // if (bluelist.size() == 0) System.out.println("BLUELIST is empty");
+                // if (bluelist.isEmpty()) System.out.println("BLUELIST is empty");
             }
         }
     }
 
     public boolean isIdentityTransformer() {
-        return (bluelist.size() == 0);
+        return bluelist.isEmpty();
     }
 
     private static char[] genBlueLetters(int length) {
diff --git a/source/net/yacy/document/parser/html/TransformerWriter.java b/source/net/yacy/document/parser/html/TransformerWriter.java
index 45c38bf6d..5564bb2ad 100644
--- a/source/net/yacy/document/parser/html/TransformerWriter.java
+++ b/source/net/yacy/document/parser/html/TransformerWriter.java
@@ -144,7 +144,7 @@ public final class TransformerWriter extends Writer {
     }
 
     public static char[] genTag0(final String tagname, final Properties tagopts, final char quotechar) {   
-            final char[] tagoptsx = (tagopts.size() == 0) ? null : genOpts(tagopts, quotechar);
+            final char[] tagoptsx = (tagopts.isEmpty()) ? null : genOpts(tagopts, quotechar);
             final CharBuffer bb = new CharBuffer(tagname.length() + ((tagoptsx == null) ? 0 : (tagoptsx.length + 1)) + tagname.length() + 2);
             bb.append((int)'<').append(tagname);
             if (tagoptsx != null) {
diff --git a/source/net/yacy/document/parser/rssParser.java b/source/net/yacy/document/parser/rssParser.java
index 23d808dcf..b282c39c5 100644
--- a/source/net/yacy/document/parser/rssParser.java
+++ b/source/net/yacy/document/parser/rssParser.java
@@ -133,17 +133,17 @@ public class rssParser extends AbstractParser implements Idiom {
                         FileUtils.copy(new ByteArrayInputStream(itemContent.getBytes("UTF-8")), writer, Charset.forName("UTF-8"));
                         
                         final String itemHeadline = scraper.getTitle();     
-                        if ((itemHeadline != null) && (itemHeadline.length() > 0)) {
+                        if (itemHeadline != null && !itemHeadline.isEmpty()) {
                             feedSections.add(itemHeadline);
                         }
                         
                         final Map<DigestURI, String> itemLinks = scraper.getAnchors();
-                        if ((itemLinks != null) && (itemLinks.size() > 0)) {
+                        if (itemLinks != null && !itemLinks.isEmpty()) {
                             anchors.putAll(itemLinks);
                         }
                         
                         final HashMap<String, ImageEntry> itemImages = scraper.getImages();
-                        if ((itemImages != null) && (itemImages.size() > 0)) {
+                        if (itemImages != null && !itemImages.isEmpty()) {
                             ContentScraper.addAllImages(images, itemImages);
                         }
                         
diff --git a/source/net/yacy/document/parser/xml/RSSFeed.java b/source/net/yacy/document/parser/xml/RSSFeed.java
index 341e0c0c1..ec0f9610f 100644
--- a/source/net/yacy/document/parser/xml/RSSFeed.java
+++ b/source/net/yacy/document/parser/xml/RSSFeed.java
@@ -111,6 +111,10 @@ public class RSSFeed implements Iterable<RSSMessage> {
         return messages.get(guid);
     }
 
+    public boolean isEmpty() {
+        return messages.isEmpty();
+    }
+    
     public int size() {
         return messages.size();
     }
@@ -121,7 +125,7 @@ public class RSSFeed implements Iterable<RSSMessage> {
     
     public RSSMessage pollMessage() {
         // retrieve and delete item
-        if (messageQueue.size() == 0) return null;
+        if (messageQueue.isEmpty()) return null;
         final String nextGUID = messageQueue.poll();
         if (nextGUID == null) return null;
         return messages.remove(nextGUID);
diff --git a/source/net/yacy/kelondro/blob/ArrayStack.java b/source/net/yacy/kelondro/blob/ArrayStack.java
index ceaeab382..18b69d99b 100755
--- a/source/net/yacy/kelondro/blob/ArrayStack.java
+++ b/source/net/yacy/kelondro/blob/ArrayStack.java
@@ -287,7 +287,7 @@ public class ArrayStack implements BLOB {
     }
     
     public synchronized File smallestBLOB(File excluding, long maxsize) {
-        if (this.blobs.size() == 0) return null;
+        if (this.blobs.isEmpty()) return null;
         File bestFile = null;
         long smallest = Long.MAX_VALUE;
         File f = null;
@@ -305,7 +305,7 @@ public class ArrayStack implements BLOB {
     }
     
     public synchronized File unmountOldestBLOB(boolean smallestFromFirst2) {
-        if (this.blobs.size() == 0) return null;
+        if (this.blobs.isEmpty()) return null;
         int idx = 0;
         if (smallestFromFirst2 && this.blobs.get(1).location.length() < this.blobs.get(0).location.length()) idx = 1;
         return unmount(idx);
@@ -313,7 +313,7 @@ public class ArrayStack implements BLOB {
     
     /*
     public synchronized File unmountSimilarSizeBLOB(long otherSize) {
-        if (this.blobs.size() == 0 || otherSize == 0) return null;
+        if (this.blobs.isEmpty() || otherSize == 0) return null;
         blobItem b;
         double delta, bestDelta = Double.MAX_VALUE;
         int bestIndex = -1;
@@ -365,10 +365,10 @@ public class ArrayStack implements BLOB {
     
     private void executeLimits() {
         // check if storage limits are reached and execute consequences
-        if (blobs.size() == 0) return;
+        if (blobs.isEmpty()) return;
         
         // age limit:
-        while (blobs.size() > 0 && System.currentTimeMillis() - blobs.get(0).creation.getTime() - this.fileAgeLimit > this.repositoryAgeMax) {
+        while (!blobs.isEmpty() && System.currentTimeMillis() - blobs.get(0).creation.getTime() - this.fileAgeLimit > this.repositoryAgeMax) {
             // too old
             blobItem oldestBLOB = blobs.remove(0);
             oldestBLOB.blob.close(false);
@@ -377,7 +377,7 @@ public class ArrayStack implements BLOB {
         }
         
         // size limit
-        while (blobs.size() > 0 && length() > this.repositorySizeMax) {
+        while (!blobs.isEmpty() && length() > this.repositorySizeMax) {
             // too large
             blobItem oldestBLOB = blobs.remove(0);
             oldestBLOB.blob.close(false);
@@ -446,6 +446,11 @@ public class ArrayStack implements BLOB {
         return s;
     }
     
+    public synchronized boolean isEmpty() {
+        for (blobItem bi: blobs) if (!bi.blob.isEmpty()) return false;
+        return true;
+    }
+    
     /**
      * ask for the number of blob entries in each blob of the blob array
      * @return the number of entries in each blob
@@ -676,7 +681,7 @@ public class ArrayStack implements BLOB {
      * @throws IOException
      */
     public synchronized void put(byte[] key, byte[] b) throws IOException {
-        blobItem bi = (blobs.size() == 0) ? null : blobs.get(blobs.size() - 1);
+        blobItem bi = (blobs.isEmpty()) ? null : blobs.get(blobs.size() - 1);
         if (bi == null)
             System.out.println("bi == null");
         else if (System.currentTimeMillis() - bi.creation.getTime() > this.fileAgeLimit)
diff --git a/source/net/yacy/kelondro/blob/BLOB.java b/source/net/yacy/kelondro/blob/BLOB.java
index 8dd3cf2b6..5b37f0c1c 100644
--- a/source/net/yacy/kelondro/blob/BLOB.java
+++ b/source/net/yacy/kelondro/blob/BLOB.java
@@ -64,6 +64,12 @@ public interface BLOB {
      */
     public int size();
     
+    /**
+     * ask if the BLOB is empty
+     * @return true iff size() == 0
+     */
+    public boolean isEmpty();
+    
     /**
      * iterator over all keys
      * @param up
diff --git a/source/net/yacy/kelondro/blob/Compressor.java b/source/net/yacy/kelondro/blob/Compressor.java
index 0feaf9ad7..33e823eda 100644
--- a/source/net/yacy/kelondro/blob/Compressor.java
+++ b/source/net/yacy/kelondro/blob/Compressor.java
@@ -221,7 +221,7 @@ public class Compressor implements BLOB {
         // check if the buffer is full or could be full after this write
         if (this.bufferlength + b.length * 2 > this.maxbufferlength) {
             // in case that we compress, just compress as much as is necessary to get enough room
-            while (this.bufferlength + b.length * 2 > this.maxbufferlength && this.buffer.size() > 0) {
+            while (this.bufferlength + b.length * 2 > this.maxbufferlength && !this.buffer.isEmpty()) {
                 flushOne();
             }
             // in case that this was not enough, just flush all
@@ -245,6 +245,12 @@ public class Compressor implements BLOB {
         return this.backend.size() + this.buffer.size();
     }
     
+    public synchronized boolean isEmpty() {
+        if (!this.backend.isEmpty()) return false;
+        if (!this.buffer.isEmpty()) return false;
+        return true;
+    }
+    
     public synchronized CloneableIterator<byte[]> keys(boolean up, boolean rotating) throws IOException {
         flushAll();
         return this.backend.keys(up, rotating);
@@ -256,7 +262,7 @@ public class Compressor implements BLOB {
     }
     
     private boolean flushOne() throws IOException {
-        if (this.buffer.size() == 0) return false;
+        if (this.buffer.isEmpty()) return false;
         // depending on process case, write it to the file or compress it to the other queue
         Map.Entry<String, byte[]> entry = this.buffer.entrySet().iterator().next();
         this.buffer.remove(entry.getKey());
@@ -268,7 +274,7 @@ public class Compressor implements BLOB {
     }
 
     private void flushAll() throws IOException {
-        while (this.buffer.size() > 0) {
+        while (!this.buffer.isEmpty()) {
             if (!flushOne()) break;
         }
         assert this.bufferlength == 0;
diff --git a/source/net/yacy/kelondro/blob/Heap.java b/source/net/yacy/kelondro/blob/Heap.java
index c72b8ff98..712c9735e 100755
--- a/source/net/yacy/kelondro/blob/Heap.java
+++ b/source/net/yacy/kelondro/blob/Heap.java
@@ -314,7 +314,7 @@ public final class Heap extends HeapModifier implements BLOB {
         if (b.length == 0) return true;
         
         // then look if we can use a free entry
-        if (this.free.size() == 0) return false;
+        if (this.free.isEmpty()) return false;
         
         // find the largest entry
         long lseek = -1;
diff --git a/source/net/yacy/kelondro/blob/HeapModifier.java b/source/net/yacy/kelondro/blob/HeapModifier.java
index 714309fda..03c0e2344 100644
--- a/source/net/yacy/kelondro/blob/HeapModifier.java
+++ b/source/net/yacy/kelondro/blob/HeapModifier.java
@@ -56,8 +56,6 @@ public class HeapModifier extends HeapReader implements BLOB {
         super(heapFile, keylength, ordering);
     }
     
-    
-    
     /**
      * clears the content of the database
      * @throws IOException
@@ -137,7 +135,7 @@ public class HeapModifier extends HeapReader implements BLOB {
         
         // first find the gap entry for the closest gap in front of the give gap
         SortedMap<Long, Integer> head = this.free.headMap(thisSeek);
-        if (head.size() == 0) return;
+        if (head.isEmpty()) return;
         long previousSeek = head.lastKey().longValue();
         int previousSize = head.get(previousSeek).intValue();
         
@@ -214,7 +212,7 @@ public class HeapModifier extends HeapReader implements BLOB {
         // find gaps at the end of the file and shrink the file by these gaps
     	if (this.free == null) return;
         try {
-            while (this.free.size() > 0) {
+            while (!this.free.isEmpty()) {
                 Long seek = this.free.lastKey();
                 int size = this.free.get(seek).intValue();
                 if (seek.longValue() + size + 4 != this.file.length()) return;
diff --git a/source/net/yacy/kelondro/blob/HeapReader.java b/source/net/yacy/kelondro/blob/HeapReader.java
index 09f451225..7f9d53cb8 100644
--- a/source/net/yacy/kelondro/blob/HeapReader.java
+++ b/source/net/yacy/kelondro/blob/HeapReader.java
@@ -154,7 +154,7 @@ public class HeapReader {
         FileUtils.deletedelete(fgf);
         
         // everything is fine now
-        return this.index.size() > 0;
+        return !this.index.isEmpty();
     }
     
     private void initIndexReadFromHeap() throws IOException {
@@ -260,6 +260,11 @@ public class HeapReader {
         return (this.index == null) ? 0 : this.index.size();
     }
     
+    public synchronized boolean isEmpty() {
+        if (this.index == null) return true;
+        return this.index.isEmpty();
+    }
+    
     /**
      * test if a key is in the heap file. This does not need any IO, because it uses only the ram index
      * @param key
diff --git a/source/net/yacy/kelondro/blob/MapDataMining.java b/source/net/yacy/kelondro/blob/MapDataMining.java
index 329a5f4fc..5648562b1 100644
--- a/source/net/yacy/kelondro/blob/MapDataMining.java
+++ b/source/net/yacy/kelondro/blob/MapDataMining.java
@@ -330,6 +330,10 @@ public class MapDataMining extends MapView {
         return super.size();
     }
     
+    public synchronized boolean isEmpty() {
+        return super.isEmpty();
+    }
+    
     public synchronized void close() {
         // close cluster
         if (sortClusterMap != null) {
diff --git a/source/net/yacy/kelondro/blob/MapView.java b/source/net/yacy/kelondro/blob/MapView.java
index 4ae58c080..14347760a 100644
--- a/source/net/yacy/kelondro/blob/MapView.java
+++ b/source/net/yacy/kelondro/blob/MapView.java
@@ -294,6 +294,10 @@ public class MapView {
         return (blob == null) ? 0 : blob.size();
     }
 
+    public synchronized boolean isEmpty() {
+        return (blob == null) ? true : blob.isEmpty();
+    }
+    
     /**
      * close the Map table
      */
diff --git a/source/net/yacy/kelondro/index/Cache.java b/source/net/yacy/kelondro/index/Cache.java
index 88e783eb4..3f4cb9a07 100644
--- a/source/net/yacy/kelondro/index/Cache.java
+++ b/source/net/yacy/kelondro/index/Cache.java
@@ -482,6 +482,10 @@ public final class Cache implements ObjectIndex, Iterable<Row.Entry> {
         return index.size();
     }
 
+    public final boolean isEmpty() {
+        return index.isEmpty();
+    }
+    
     public final String filename() {
         return index.filename();
     }
diff --git a/source/net/yacy/kelondro/index/HandleMap.java b/source/net/yacy/kelondro/index/HandleMap.java
index abc167ac2..a42743ad3 100644
--- a/source/net/yacy/kelondro/index/HandleMap.java
+++ b/source/net/yacy/kelondro/index/HandleMap.java
@@ -262,6 +262,10 @@ public final class HandleMap implements Iterable<Row.Entry> {
         return index.size();
     }
     
+    public final synchronized boolean isEmpty() {
+        return index.isEmpty();
+    }
+    
     public final synchronized CloneableIterator<byte[]> keys(final boolean up, final byte[] firstKey) {
         return index.keys(up, firstKey);
     }
diff --git a/source/net/yacy/kelondro/index/ObjectArrayCache.java b/source/net/yacy/kelondro/index/ObjectArrayCache.java
index 2a00e284c..bc2c98e07 100644
--- a/source/net/yacy/kelondro/index/ObjectArrayCache.java
+++ b/source/net/yacy/kelondro/index/ObjectArrayCache.java
@@ -143,7 +143,7 @@ public final class ObjectArrayCache {
         }
         // at this point index1 cannot be null
         assert (index1 != null);
-        if (index1.size() == 0) return null;
+        if (index1.isEmpty()) return null;
         final Row.Entry indexentry = index1.remove(key);
         if (indexentry == null) return null;
         return indexentry.getColBytes(1);
@@ -226,7 +226,7 @@ public final class ObjectArrayCache {
 			jcontrol.add(Long.valueOf(r));
 			kcontrol.putb((int) r, "x".getBytes());
 			if (random.nextLong() % 5 == 0) ra.add(Long.valueOf(r));
-			if ((ra.size() > 0) && (random.nextLong() % 7 == 0)) {
+			if (!ra.isEmpty() && random.nextLong() % 7 == 0) {
 				rc++;
 				p = Math.abs(random.nextInt() % ra.size());
 				R = ra.get(p);
diff --git a/source/net/yacy/kelondro/index/ObjectIndex.java b/source/net/yacy/kelondro/index/ObjectIndex.java
index 664874f4c..d2bc5c685 100644
--- a/source/net/yacy/kelondro/index/ObjectIndex.java
+++ b/source/net/yacy/kelondro/index/ObjectIndex.java
@@ -42,6 +42,7 @@ public interface ObjectIndex {
 
     public String filename(); // returns a unique identified for this index; can be a real or artificial file name
     public int size();
+    public boolean isEmpty();
     public Row row();
     public boolean has(byte[] key); // use this only if there is no get in case that has returns true
     public Row.Entry get(byte[] key) throws IOException;
diff --git a/source/net/yacy/kelondro/index/ObjectIndexCache.java b/source/net/yacy/kelondro/index/ObjectIndexCache.java
index 051aaeef5..2fddb8364 100644
--- a/source/net/yacy/kelondro/index/ObjectIndexCache.java
+++ b/source/net/yacy/kelondro/index/ObjectIndexCache.java
@@ -210,6 +210,20 @@ public final class ObjectIndexCache implements ObjectIndex, Iterable<Row.Entry>
         return index0.size() + index1.size();
     }
     
+    public final synchronized boolean isEmpty() {
+        if ((index0 != null) && (index1 == null)) {
+            return index0.isEmpty();
+        }
+        if ((index0 == null) && (index1 != null)) {
+            return index1.isEmpty();
+        }
+        assert ((index0 != null) && (index1 != null));
+        if (!index0.isEmpty()) return false;
+        if (!index1.isEmpty()) return false;
+        return true;
+    }
+    
+    
     public final synchronized CloneableIterator<byte[]> keys(final boolean up, final byte[] firstKey) {
         // returns the key-iterator of the underlying kelondroIndex
         if (index1 == null) {
diff --git a/source/net/yacy/kelondro/index/RowCollection.java b/source/net/yacy/kelondro/index/RowCollection.java
index 4006f6c5c..7b03cf022 100644
--- a/source/net/yacy/kelondro/index/RowCollection.java
+++ b/source/net/yacy/kelondro/index/RowCollection.java
@@ -452,6 +452,10 @@ public class RowCollection implements Iterable<Row.Entry> {
         return this.chunkcount;
     }
     
+    public boolean isEmpty() {
+        return this.chunkcount == 0;
+    }
+    
     public int sorted() {
         return this.sortBound;
     }
@@ -853,7 +857,7 @@ public class RowCollection implements Iterable<Row.Entry> {
                     removeRow(i + 1, false);
                     d++;
                     if (i + 1 < chunkcount - 1) u = false;
-                } else if (collection.size() > 0) {
+                } else if (!collection.isEmpty()) {
                     // finish collection of double occurrences
                     collection.addUnique(get(i + 1, false));
                     removeRow(i + 1, false);
diff --git a/source/net/yacy/kelondro/index/RowSetArray.java b/source/net/yacy/kelondro/index/RowSetArray.java
index 8c9a4a2d7..da7c78ae8 100644
--- a/source/net/yacy/kelondro/index/RowSetArray.java
+++ b/source/net/yacy/kelondro/index/RowSetArray.java
@@ -143,7 +143,7 @@ public final class RowSetArray implements ObjectIndex, Iterable<Row.Entry> {
             for (int i = 0; i < this.array.length; i++) {
                 if (this.array[i] != null) {
                     col.addAll(this.array[i].removeDoubles());
-                    if (this.array[i].size() == 0) this.array[i] = null;
+                    if (this.array[i].isEmpty()) this.array[i] = null;
                 }
             }
         }
@@ -155,7 +155,7 @@ public final class RowSetArray implements ObjectIndex, Iterable<Row.Entry> {
             for (int i = 0; i < this.array.length; i++) {
                 if (this.array[i] != null) {
                     Entry entry = this.array[i].removeOne();
-                    if (this.array[i].size() == 0) this.array[i] = null;
+                    if (this.array[i].isEmpty()) this.array[i] = null;
                     return entry;
                 }
             }
@@ -202,6 +202,17 @@ public final class RowSetArray implements ObjectIndex, Iterable<Row.Entry> {
         return c;
     }
 
+    public final boolean isEmpty() {
+        synchronized (this.array) {
+            for (int i = 0; i < this.array.length; i++) {
+                if (this.array[i] != null) {
+                    if (!this.array[i].isEmpty()) return false;
+                }
+            }
+        }
+        return true;
+    }
+    
     public final Iterator<Entry> iterator() {
         return this.rows(true, null);
     }
diff --git a/source/net/yacy/kelondro/order/MergeIterator.java b/source/net/yacy/kelondro/order/MergeIterator.java
index ef10120ca..1893d132d 100644
--- a/source/net/yacy/kelondro/order/MergeIterator.java
+++ b/source/net/yacy/kelondro/order/MergeIterator.java
@@ -136,7 +136,7 @@ public class MergeIterator<E> implements CloneableIterator<E> {
         // this extends the ability to combine two iterators
         // to the ability of combining a set of iterators
         if (iterators == null) return null;
-        if (iterators.size() == 0) return null;
+        if (iterators.isEmpty()) return null;
         return cascade(iterators.iterator(), c, merger, up);
     }
     
diff --git a/source/net/yacy/kelondro/order/StackIterator.java b/source/net/yacy/kelondro/order/StackIterator.java
index ef75c7364..4ef50cda5 100644
--- a/source/net/yacy/kelondro/order/StackIterator.java
+++ b/source/net/yacy/kelondro/order/StackIterator.java
@@ -91,7 +91,7 @@ public class StackIterator<E> implements CloneableIterator<E> {
         // this extends the ability to combine two iterators
         // to the ability of combining a set of iterators
         if (iterators == null) return null;
-        if (iterators.size() == 0) return null;
+        if (iterators.isEmpty()) return null;
         return stack(iterators.iterator());
     }
     
diff --git a/source/net/yacy/kelondro/rwi/AbstractBufferedIndex.java b/source/net/yacy/kelondro/rwi/AbstractBufferedIndex.java
index 0e31459e6..b5ee47a62 100644
--- a/source/net/yacy/kelondro/rwi/AbstractBufferedIndex.java
+++ b/source/net/yacy/kelondro/rwi/AbstractBufferedIndex.java
@@ -58,7 +58,7 @@ public abstract class AbstractBufferedIndex<ReferenceType extends Reference> ext
         // It must also be ensured that the counter is in/decreased every loop
         while ((count > 0) && (i.hasNext())) {
             container = i.next();
-            if ((container != null) && (container.size() > 0)) {
+            if (container != null && !container.isEmpty()) {
                 containers.add(container);
             }
             count--; // decrease counter even if the container was null or empty to ensure termination
diff --git a/source/net/yacy/kelondro/rwi/AbstractIndex.java b/source/net/yacy/kelondro/rwi/AbstractIndex.java
index db8de14fb..428ade6a1 100644
--- a/source/net/yacy/kelondro/rwi/AbstractIndex.java
+++ b/source/net/yacy/kelondro/rwi/AbstractIndex.java
@@ -71,7 +71,7 @@ public abstract class AbstractIndex <ReferenceType extends Reference> implements
         // It must also be ensured that the counter is in/decreased every loop
         while ((count > 0) && (i.hasNext())) {
             container = i.next();
-            if ((container != null) && (container.size() > 0)) {
+            if (container != null && !container.isEmpty()) {
                 containers.add(container);
             }
             count--; // decrease counter even if the container was null or empty to ensure termination
@@ -117,7 +117,7 @@ public abstract class AbstractIndex <ReferenceType extends Reference> implements
             }
         
             // check result
-            if ((singleContainer == null || singleContainer.size() == 0)) return new HashMap<byte[], ReferenceContainer<ReferenceType>>(0);
+            if ((singleContainer == null || singleContainer.isEmpty())) return new HashMap<byte[], ReferenceContainer<ReferenceType>>(0);
         
             containers.put(singleHash, singleContainer);
         }
@@ -154,13 +154,13 @@ public abstract class AbstractIndex <ReferenceType extends Reference> implements
             }
         
             // check result
-            if ((singleContainer == null || singleContainer.size() == 0)) return ReferenceContainer.emptyContainer(factory, null, 0);
+            if ((singleContainer == null || singleContainer.isEmpty())) return ReferenceContainer.emptyContainer(factory, null, 0);
             if (resultContainer == null) resultContainer = singleContainer; else {
                 resultContainer = ReferenceContainer.joinConstructive(factory, resultContainer, singleContainer, maxDistance);
             }
             
             // finish if the result is empty
-            if (resultContainer.size() == 0) return resultContainer;
+            if (resultContainer.isEmpty()) return resultContainer;
         }
         return resultContainer;
     }
diff --git a/source/net/yacy/kelondro/rwi/AbstractReference.java b/source/net/yacy/kelondro/rwi/AbstractReference.java
index 8d9e77495..70b601a11 100644
--- a/source/net/yacy/kelondro/rwi/AbstractReference.java
+++ b/source/net/yacy/kelondro/rwi/AbstractReference.java
@@ -37,7 +37,7 @@ public abstract class AbstractReference implements Reference {
         return l;
     }
     protected static int max(ArrayList<Integer> a) {
-        assert a.size() > 0;
+        assert !a.isEmpty();
         if (a.size() == 1) return a.get(0);
         if (a.size() == 2) return Math.max(a.get(0), a.get(1));
         int r = a.get(0);
@@ -45,7 +45,7 @@ public abstract class AbstractReference implements Reference {
         return r;
     }
     protected static int min(ArrayList<Integer> a) {
-        assert a.size() > 0;
+        assert !a.isEmpty();
         if (a.size() == 1) return a.get(0);
         if (a.size() == 2) return Math.min(a.get(0), a.get(1));
         int r = a.get(0);
diff --git a/source/net/yacy/kelondro/rwi/IODispatcher.java b/source/net/yacy/kelondro/rwi/IODispatcher.java
index 882f75613..c6a3bc621 100644
--- a/source/net/yacy/kelondro/rwi/IODispatcher.java
+++ b/source/net/yacy/kelondro/rwi/IODispatcher.java
@@ -83,7 +83,7 @@ public class IODispatcher extends Thread {
     public synchronized void dump(ReferenceContainerCache<? extends Reference> cache, File file, ReferenceContainerArray<? extends Reference> array) {
         if (dumpQueue == null || controlQueue == null || !this.isAlive()) {
             Log.logWarning("IODispatcher", "emergency dump of file " + file.getName());
-             if (cache.size() > 0) cache.dump(file, (int) Math.min(MemoryControl.available() / 3, writeBufferSize));
+             if (!cache.isEmpty()) cache.dump(file, (int) Math.min(MemoryControl.available() / 3, writeBufferSize));
         } else {
             DumpJob<? extends Reference> job = (DumpJob<? extends Reference>)new DumpJob(cache, file, array);
             try {
@@ -145,7 +145,7 @@ public class IODispatcher extends Thread {
                 controlQueue.acquire();
                 
                 // prefer dump actions to flush memory to disc
-                if (dumpQueue.size() > 0) {
+                if (!dumpQueue.isEmpty()) {
                 	File f = null;
                     try {
                         dumpJob = dumpQueue.take();
@@ -162,7 +162,7 @@ public class IODispatcher extends Thread {
                 }
                 
                 // otherwise do a merge operation
-                if (mergeQueue.size() > 0) {
+                if (!mergeQueue.isEmpty()) {
                 	File f = null, f1 = null, f2 = null;
                     try {
                         mergeJob = mergeQueue.take();
@@ -216,7 +216,7 @@ public class IODispatcher extends Thread {
         }
         public void dump() {
             try {
-                if (cache.size() > 0) cache.dump(file, (int) Math.min(MemoryControl.available() / 3, writeBufferSize));
+                if (!cache.isEmpty()) cache.dump(file, (int) Math.min(MemoryControl.available() / 3, writeBufferSize));
                 array.mountBLOBFile(file);
             } catch (IOException e) {
                 Log.logException(e);
diff --git a/source/net/yacy/kelondro/rwi/IndexCell.java b/source/net/yacy/kelondro/rwi/IndexCell.java
index 57296e6d5..cc11b24c1 100644
--- a/source/net/yacy/kelondro/rwi/IndexCell.java
+++ b/source/net/yacy/kelondro/rwi/IndexCell.java
@@ -286,7 +286,7 @@ public final class IndexCell<ReferenceType extends Reference> extends AbstractBu
      * and is composed of the current date and the cell salt
      */
     public synchronized void close() {
-        if (this.ram.size() > 0) this.ram.dump(this.array.newContainerBLOBFile(), (int) Math.min(MemoryControl.available() / 3, writeBufferSize));
+        if (!this.ram.isEmpty()) this.ram.dump(this.array.newContainerBLOBFile(), (int) Math.min(MemoryControl.available() / 3, writeBufferSize));
         // close all
         this.ram.close();
         this.array.close();
diff --git a/source/net/yacy/kelondro/rwi/ReferenceContainer.java b/source/net/yacy/kelondro/rwi/ReferenceContainer.java
index 3744ccc83..5c6b05c8d 100644
--- a/source/net/yacy/kelondro/rwi/ReferenceContainer.java
+++ b/source/net/yacy/kelondro/rwi/ReferenceContainer.java
@@ -262,7 +262,7 @@ public class ReferenceContainer<ReferenceType extends Reference> extends RowSet
             singleContainer = i.next();
             
             // check result
-            if ((singleContainer == null) || (singleContainer.size() == 0)) return null; // as this is a cunjunction of searches, we have no result if any word is not known
+            if (singleContainer == null || singleContainer.isEmpty()) return null; // as this is a cunjunction of searches, we have no result if any word is not known
             
             // store result in order of result size
             map.put(Long.valueOf(singleContainer.size() * 1000 + count), singleContainer);
@@ -270,13 +270,13 @@ public class ReferenceContainer<ReferenceType extends Reference> extends RowSet
         }
         
         // check if there is any result
-        if (map.size() == 0) return null; // no result, nothing found
+        if (map.isEmpty()) return null; // no result, nothing found
         
         // the map now holds the search results in order of number of hits per word
         // we now must pairwise build up a conjunction of these sets
         Long k = map.firstKey(); // the smallest, which means, the one with the least entries
         ReferenceContainer<ReferenceType> searchA, searchB, searchResult = map.remove(k);
-        while ((map.size() > 0) && (searchResult.size() > 0)) {
+        while (!map.isEmpty() && !searchResult.isEmpty()) {
             // take the first element of map which is a result and combine it with result
             k = map.firstKey(); // the next smallest...
             searchA = searchResult;
@@ -288,7 +288,7 @@ public class ReferenceContainer<ReferenceType extends Reference> extends RowSet
         }
 
         // in 'searchResult' is now the combined search result
-        if (searchResult.size() == 0) return null;
+        if (searchResult.isEmpty()) return null;
         return searchResult;
     }
     
@@ -298,12 +298,12 @@ public class ReferenceContainer<ReferenceType extends Reference> extends RowSet
                             final Collection<ReferenceContainer<ReferenceType>> containers) {
         
         // check if there is any result
-        if ((containers == null) || (containers.size() == 0)) return pivot; // no result, nothing found
+        if (containers == null || containers.isEmpty()) return pivot; // no result, nothing found
         
         final Iterator<ReferenceContainer<ReferenceType>> i = containers.iterator();
         while (i.hasNext()) {
         	pivot = excludeDestructive(factory, pivot, i.next());
-        	if ((pivot == null) || (pivot.size() == 0)) return null;
+        	if (pivot == null || pivot.isEmpty()) return null;
         }
         
         return pivot;
@@ -322,7 +322,7 @@ public class ReferenceContainer<ReferenceType extends Reference> extends RowSet
             final ReferenceContainer<ReferenceType> i2,
             final int maxDistance) {
         if ((i1 == null) || (i2 == null)) return null;
-        if ((i1.size() == 0) || (i2.size() == 0)) return null;
+        if (i1.isEmpty() || i2.isEmpty()) return null;
         
         // decide which method to use
         final int high = ((i1.size() > i2.size()) ? i1.size() : i2.size());
@@ -418,8 +418,8 @@ public class ReferenceContainer<ReferenceType extends Reference> extends RowSet
             final ReferenceContainer<ReferenceType> excl) {
         if (pivot == null) return null;
         if (excl == null) return pivot;
-        if (pivot.size() == 0) return null;
-        if (excl.size() == 0) return pivot;
+        if (pivot.isEmpty()) return null;
+        if (excl.isEmpty()) return pivot;
         
         // decide which method to use
         final int high = ((pivot.size() > excl.size()) ? pivot.size() : excl.size());
diff --git a/source/net/yacy/kelondro/rwi/ReferenceContainerCache.java b/source/net/yacy/kelondro/rwi/ReferenceContainerCache.java
index 3b33ac0e2..788fc0b90 100644
--- a/source/net/yacy/kelondro/rwi/ReferenceContainerCache.java
+++ b/source/net/yacy/kelondro/rwi/ReferenceContainerCache.java
@@ -146,7 +146,10 @@ public final class ReferenceContainerCache<ReferenceType extends Reference> exte
         return (this.cache == null) ? 0 : this.cache.size();
     }
     
-    
+    public boolean isEmpty() {
+        if (this.cache == null) return true;
+        return this.cache.isEmpty();
+    }
 
     public int maxReferences() {
         // iterate to find the max score
@@ -298,7 +301,7 @@ public final class ReferenceContainerCache<ReferenceType extends Reference> exte
 	        final ReferenceContainer<ReferenceType> c = cache.get(tha);
 	        if ((c != null) && (c.remove(urlHash) != null)) {
 	            // removal successful
-	            if (c.size() == 0) {
+	            if (c.isEmpty()) {
 	                delete(termHash);
 	            } else {
 	                cache.put(tha, c);
@@ -311,14 +314,14 @@ public final class ReferenceContainerCache<ReferenceType extends Reference> exte
     
     public int remove(final byte[] termHash, final Set<String> urlHashes) {
         assert this.cache != null;
-        if (urlHashes.size() == 0) return 0;
+        if (urlHashes.isEmpty()) return 0;
         ByteArray tha = new ByteArray(termHash);
         int count;
         synchronized (cache) {
 	        final ReferenceContainer<ReferenceType> c = cache.get(tha);
 	        if ((c != null) && ((count = c.removeEntries(urlHashes)) > 0)) {
 	            // removal successful
-	            if (c.size() == 0) {
+	            if (c.isEmpty()) {
 	                delete(termHash);
 	            } else {
 	                cache.put(tha, c);
@@ -332,7 +335,7 @@ public final class ReferenceContainerCache<ReferenceType extends Reference> exte
     public void add(final ReferenceContainer<ReferenceType> container) {
         // this puts the entries into the cache
     	assert this.cache != null;
-        if (this.cache == null || container == null || container.size() == 0) return;
+        if (this.cache == null || container == null || container.isEmpty()) return;
         
         // put new words into cache
         ByteArray tha = new ByteArray(container.getTermHash());
diff --git a/source/net/yacy/kelondro/rwi/TermSearch.java b/source/net/yacy/kelondro/rwi/TermSearch.java
index 3adaccb8b..4b0740e53 100644
--- a/source/net/yacy/kelondro/rwi/TermSearch.java
+++ b/source/net/yacy/kelondro/rwi/TermSearch.java
@@ -46,7 +46,7 @@ public class TermSearch <ReferenceType extends Reference> {
             int maxDistance) {
         
         this.inclusionContainers =
-            (queryHashes.size() == 0) ?
+            (queryHashes.isEmpty()) ?
                 new HashMap<byte[], ReferenceContainer<ReferenceType>>(0) :
                 base.searchConjunction(queryHashes, urlselection);
                 
@@ -55,7 +55,7 @@ public class TermSearch <ReferenceType extends Reference> {
             inclusionContainers = new HashMap<byte[], ReferenceContainer<ReferenceType>>(0); // prevent that only a subset is returned
         
         HashMap<byte[], ReferenceContainer<ReferenceType>> exclusionContainers =
-            (inclusionContainers.size() == 0) ?
+            (inclusionContainers.isEmpty()) ?
                 new HashMap<byte[], ReferenceContainer<ReferenceType>>(0) :
                 base.searchConjunction(excludeHashes, urlselection);
     
diff --git a/source/net/yacy/kelondro/table/RecordStack.java b/source/net/yacy/kelondro/table/RecordStack.java
index b202f3a7a..0beb8e24f 100644
--- a/source/net/yacy/kelondro/table/RecordStack.java
+++ b/source/net/yacy/kelondro/table/RecordStack.java
@@ -237,7 +237,7 @@ public final class RecordStack extends Records {
     
     private Node topNode() throws IOException {
         // return node ontop of the stack
-        if (size() == 0) return null;
+        if (isEmpty()) return null;
         final Records.Handle h = getHandle(toor);
         if (h == null) return null;
         return new Node(h);
@@ -245,7 +245,7 @@ public final class RecordStack extends Records {
     
     private Node botNode() throws IOException {
         // return node on bottom of the stack
-        if (size() == 0) {
+        if (isEmpty()) {
         	Log.logInfo("Stack", "size() == 0");
         	return null;
         }
diff --git a/source/net/yacy/kelondro/table/SQLTable.java b/source/net/yacy/kelondro/table/SQLTable.java
index 1f93d78fa..e103bc303 100644
--- a/source/net/yacy/kelondro/table/SQLTable.java
+++ b/source/net/yacy/kelondro/table/SQLTable.java
@@ -138,6 +138,10 @@ public class SQLTable implements ObjectIndex, Iterable<Row.Entry> {
         }
     }
     
+    public boolean isEmpty() {
+        return size() == 0;
+    }
+    
     public Row row() {
         return this.rowdef;
     }
diff --git a/source/net/yacy/kelondro/table/SplitTable.java b/source/net/yacy/kelondro/table/SplitTable.java
index f21aa151b..fe0b42be0 100644
--- a/source/net/yacy/kelondro/table/SplitTable.java
+++ b/source/net/yacy/kelondro/table/SplitTable.java
@@ -186,7 +186,7 @@ public class SplitTable implements ObjectIndex, Iterable<Row.Entry> {
         String maxf;
         long maxram;
         ObjectIndex table;
-        while (t.size() > 0) {
+        while (!t.isEmpty()) {
             // find maximum table
             maxram = 0;
             maxf = null;
@@ -260,6 +260,12 @@ public class SplitTable implements ObjectIndex, Iterable<Row.Entry> {
         return s;
     }
     
+    public boolean isEmpty() {
+        final Iterator<ObjectIndex> i = tables.values().iterator();
+        while (i.hasNext()) if (!i.next().isEmpty()) return false;
+        return true;
+    }
+    
     public int writeBufferSize() {
         int s = 0;
         for (final ObjectIndex index : tables.values()) {
diff --git a/source/net/yacy/kelondro/table/Table.java b/source/net/yacy/kelondro/table/Table.java
index 5577969ef..cecc19e4d 100644
--- a/source/net/yacy/kelondro/table/Table.java
+++ b/source/net/yacy/kelondro/table/Table.java
@@ -200,7 +200,7 @@ public class Table implements ObjectIndex, Iterable<Row.Entry> {
                 final ArrayList<Long[]> doubles = index.removeDoubles();
                 //assert index.size() + doubles.size() + fail == i;
                 //System.out.println(" -removed " + doubles.size() + " doubles- done.");
-                if (doubles.size() > 0) {
+                if (!doubles.isEmpty()) {
                     Log.logInfo("TABLE", tablefile + ": WARNING - TABLE " + tablefile + " has " + doubles.size() + " doubles");
                     // from all the doubles take one, put it back to the index and remove the others from the file
                     // first put back one element each
@@ -219,7 +219,7 @@ public class Table implements ObjectIndex, Iterable<Row.Entry> {
                     }
                     // now remove the entries in a sorted way (top-down)
                     Long top;
-                    while (delpos.size() > 0) {
+                    while (!delpos.isEmpty()) {
                         top = delpos.last();
                         delpos.remove(top);
                         removeInFile(top.intValue());
@@ -337,7 +337,7 @@ public class Table implements ObjectIndex, Iterable<Row.Entry> {
         }
         // finally delete the affected rows, but start with largest id first, otherwise we overwrite wrong entries
         Long s;
-        while (d.size() > 0) {
+        while (!d.isEmpty()) {
             s = d.last();
             d.remove(s);
             this.removeInFile(s.intValue());
@@ -629,6 +629,10 @@ public class Table implements ObjectIndex, Iterable<Row.Entry> {
         return index.size();
     }
     
+    public synchronized boolean isEmpty() {
+        return index.isEmpty();
+    }
+    
     public Iterator<Entry> iterator() {
         try {
             return rows();
diff --git a/source/net/yacy/kelondro/util/MemoryTracker.java b/source/net/yacy/kelondro/util/MemoryTracker.java
index b0ad7f9fc..8a0808eab 100644
--- a/source/net/yacy/kelondro/util/MemoryTracker.java
+++ b/source/net/yacy/kelondro/util/MemoryTracker.java
@@ -98,7 +98,7 @@ public class MemoryTracker extends Thread {
             if (history.size() % 10 == 0) { // reduce number of System.currentTimeMillis() calls
                 Event e;
                 final long now = System.currentTimeMillis();
-                while (history.size() > 0) {
+                while (!history.isEmpty()) {
                     e = history.get(0);
                     if (now - e.time < 600000) break;
                     history.remove(0);
diff --git a/source/net/yacy/kelondro/util/ObjectSpace.java b/source/net/yacy/kelondro/util/ObjectSpace.java
index 1616d5986..6a83f1775 100644
--- a/source/net/yacy/kelondro/util/ObjectSpace.java
+++ b/source/net/yacy/kelondro/util/ObjectSpace.java
@@ -58,7 +58,7 @@ public class ObjectSpace {
         incAlive(len);
         synchronized (objHeap) {
             final ArrayList<byte[]> buf = objHeap.get(Integer.valueOf(len));
-            if ((buf == null) || (buf.size() == 0)) return new byte[len];
+            if (buf == null || buf.isEmpty()) return new byte[len];
             return buf.remove(buf.size() - 1);
         }
     }
diff --git a/source/net/yacy/kelondro/util/ScoreCluster.java b/source/net/yacy/kelondro/util/ScoreCluster.java
index a57d50c98..dde06a561 100644
--- a/source/net/yacy/kelondro/util/ScoreCluster.java
+++ b/source/net/yacy/kelondro/util/ScoreCluster.java
@@ -176,6 +176,10 @@ public final class ScoreCluster<E> {
         return refkeyDB.size();
     }
     
+    public synchronized boolean isEmpty() {
+        return refkeyDB.isEmpty();
+    }
+    
     public synchronized void incScore(final E[] objs) {
         for (int i = 0; i < objs.length; i++) addScore(objs[i], 1);
     }
@@ -293,22 +297,22 @@ public final class ScoreCluster<E> {
     }
     
     public synchronized int getMaxScore() {
-        if (refkeyDB.size() == 0) return -1;
+        if (refkeyDB.isEmpty()) return -1;
         return (int) ((keyrefDB.lastKey().longValue() & 0xFFFFFFFF00000000L) >> 32);
     }
 
     public synchronized int getMinScore() {
-        if (refkeyDB.size() == 0) return -1;
+        if (refkeyDB.isEmpty()) return -1;
         return (int) ((keyrefDB.firstKey().longValue() & 0xFFFFFFFF00000000L) >> 32);
     }
 
     public synchronized E getMaxObject() {
-        if (refkeyDB.size() == 0) return null;
+        if (refkeyDB.isEmpty()) return null;
         return keyrefDB.get(keyrefDB.lastKey());
     }
     
     public synchronized E getMinObject() {
-        if (refkeyDB.size() == 0) return null;
+        if (refkeyDB.isEmpty()) return null;
         return keyrefDB.get(keyrefDB.firstKey());
     }
     
@@ -368,7 +372,7 @@ public final class ScoreCluster<E> {
         private void internalNext() {
             Long key;
             int score = (max + min) / 2;
-            while (keyrefDBcopy.size() > 0) {
+            while (!keyrefDBcopy.isEmpty()) {
                 key = ((up) ? keyrefDBcopy.firstKey() : keyrefDBcopy.lastKey());
                 n = keyrefDBcopy.remove(key);
                 score = (int) ((key.longValue() & 0xFFFFFFFF00000000L) >> 32);
@@ -404,7 +408,7 @@ public final class ScoreCluster<E> {
         }
        
         public boolean hasNext() {
-            return view.size() > 0;
+            return !view.isEmpty();
         }
         
         public E next() {
diff --git a/source/net/yacy/kelondro/util/SetTools.java b/source/net/yacy/kelondro/util/SetTools.java
index 56e39f141..0125aa1a4 100644
--- a/source/net/yacy/kelondro/util/SetTools.java
+++ b/source/net/yacy/kelondro/util/SetTools.java
@@ -78,7 +78,7 @@ public class SetTools {
             singleMap = i.next();
             
             // check result
-            if ((singleMap == null) || (singleMap.size() == 0)) return new TreeMap<A, B>();
+            if ((singleMap == null) || (singleMap.isEmpty())) return new TreeMap<A, B>();
             
             // store result in order of result size
             orderMap.put(Long.valueOf(singleMap.size() * 1000 + count), singleMap);
@@ -86,12 +86,12 @@ public class SetTools {
         }
         
         // check if there is any result
-        if (orderMap.size() == 0) return new TreeMap<A, B>();
+        if (orderMap.isEmpty()) return new TreeMap<A, B>();
         
         // we now must pairwise build up a conjunction of these maps
         Long k = orderMap.firstKey(); // the smallest, which means, the one with the least entries
         TreeMap<A, B> mapA, mapB, joinResult = orderMap.remove(k);
-        while ((orderMap.size() > 0) && (joinResult.size() > 0)) {
+        while (!orderMap.isEmpty() && !joinResult.isEmpty()) {
             // take the first element of map which is a result and combine it with result
             k = orderMap.firstKey(); // the next smallest...
             mapA = joinResult;
@@ -103,7 +103,7 @@ public class SetTools {
         }
 
         // in 'searchResult' is now the combined search result
-        if (joinResult.size() == 0) return new TreeMap<A, B>();
+        if (joinResult.isEmpty()) return new TreeMap<A, B>();
         return joinResult;
     }
     
@@ -111,7 +111,7 @@ public class SetTools {
         // comparators must be equal
         if ((map1 == null) || (map2 == null)) return null;
         if (map1.comparator() != map2.comparator()) return null;
-        if ((map1.size() == 0) || (map2.size() == 0)) return new TreeMap<A, B>(map1.comparator());
+        if (map1.isEmpty() || map2.isEmpty()) return new TreeMap<A, B>(map1.comparator());
 
         // decide which method to use
         final int high = ((map1.size() > map2.size()) ? map1.size() : map2.size());
@@ -183,7 +183,7 @@ public class SetTools {
     	// comparators must be equal
         if ((set1 == null) || (set2 == null)) return null;
         if (set1.comparator() != set2.comparator()) return null;
-        if ((set1.size() == 0) || (set2.size() == 0)) return new TreeSet<A>(set1.comparator());
+        if (set1.isEmpty() || set2.isEmpty()) return new TreeSet<A>(set1.comparator());
 
         // decide which method to use
         final int high = ((set1.size() > set2.size()) ? set1.size() : set2.size());
@@ -241,7 +241,7 @@ public class SetTools {
 		// comparators must be equal
 		if ((set1 == null) || (set2 == null)) return false;
 		if (set1.comparator() != set2.comparator()) return false;
-		if ((set1.size() == 0) || (set2.size() == 0)) return false;
+		if (set1.isEmpty() || set2.isEmpty()) return false;
 
 		// decide which method to use
 		final int high = ((set1.size() > set2.size()) ? set1.size() : set2.size());
@@ -297,7 +297,7 @@ public class SetTools {
     public static <A, B> TreeMap<A, B> excludeConstructive(final TreeMap<A, B> map, final Set<A> set) {
         if (map == null) return null;
         if (set == null) return map;
-        if ((map.size() == 0) || (set.size() == 0)) return map;
+        if (map.isEmpty() || set.isEmpty()) return map;
         assert !(set instanceof TreeSet) || map.comparator() == ((TreeSet<A>) set).comparator();
         // if (map.comparator() != set.comparator()) return excludeConstructiveByTestMapInSet(map, set);
         return excludeConstructiveByTestMapInSet(map, set);
@@ -320,7 +320,7 @@ public class SetTools {
         if (map == null) return;
         if (set == null) return;
         assert !(map instanceof TreeMap && set instanceof TreeSet) || ((TreeMap<A, B>) map).comparator() == ((TreeSet<A>) set).comparator();
-        if ((map.size() == 0) || (set.size() == 0)) return;
+        if (map.isEmpty() || set.isEmpty()) return;
 
         if (map.size() < set.size())
             excludeDestructiveByTestMapInSet(map, set);
@@ -343,7 +343,7 @@ public class SetTools {
         if (set1 == null) return;
         if (set2 == null) return;
         assert !(set1 instanceof TreeSet && set2 instanceof TreeSet) || ((TreeSet<A>) set1).comparator() == ((TreeSet<A>) set2).comparator();
-        if ((set1.size() == 0) || (set2.size() == 0)) return;
+        if (set1.isEmpty() || set2.isEmpty()) return;
         
         if (set1.size() < set2.size())
             excludeDestructiveByTestSmallInLarge(set1, set2);
diff --git a/source/net/yacy/kelondro/util/SortStack.java b/source/net/yacy/kelondro/util/SortStack.java
index 2428db8f4..3ffdd464e 100644
--- a/source/net/yacy/kelondro/util/SortStack.java
+++ b/source/net/yacy/kelondro/util/SortStack.java
@@ -56,6 +56,11 @@ public class SortStack<E> {
         this.maxsize = maxsize;
     }
 
+    
+    public boolean isEmpty() {
+        return this.instack.isEmpty();
+    }
+    
     public int size() {
         return this.instack.size();
     }
@@ -82,8 +87,8 @@ public class SortStack<E> {
 
         // check maximum size of the stack an remove elements if the stack gets too large
         if (this.maxsize <= 0) return;
-        while ((this.onstack.size() > 0) && (this.onstack.size() > this.maxsize)) synchronized (this.onstack) {
-            if ((this.onstack.size() > 0) && (this.onstack.size() > this.maxsize)) {
+        while (!this.onstack.isEmpty() && this.onstack.size() > this.maxsize) synchronized (this.onstack) {
+            if (!this.onstack.isEmpty() && this.onstack.size() > this.maxsize) {
                 this.onstack.remove(this.onstack.lastKey());
             }
         }
@@ -121,7 +126,7 @@ public class SortStack<E> {
             final List<E> l = this.onstack.get(w);
             element = l.remove(0);
             this.instack.remove(element);
-            if (l.size() == 0) this.onstack.remove(w);
+            if (l.isEmpty()) this.onstack.remove(w);
         }
         return new stackElement(element, w);
     }
@@ -140,7 +145,7 @@ public class SortStack<E> {
                 while (i.hasNext()) {
                     if (i.next().equals(element)) {
                         i.remove();
-                        if (entry.getValue().size() == 0) {
+                        if (entry.getValue().isEmpty()) {
                             this.onstack.remove(entry.getKey());
                         }
                         return;
@@ -152,7 +157,7 @@ public class SortStack<E> {
     
     public boolean bottom(final long weight) {
         // returns true if the element with that weight would be on the bottom of the stack after inserting
-        if (this.onstack.size() == 0) return true;
+        if (this.onstack.isEmpty()) return true;
         Long l;
         synchronized (this.onstack) {
             l = this.onstack.lastKey();
diff --git a/source/net/yacy/kelondro/util/SortStore.java b/source/net/yacy/kelondro/util/SortStore.java
index 8328691db..6f8d7f3fa 100644
--- a/source/net/yacy/kelondro/util/SortStore.java
+++ b/source/net/yacy/kelondro/util/SortStore.java
@@ -54,6 +54,11 @@ public class SortStore<E> extends SortStack<E> {
         this.offset = new ConcurrentHashMap<E, Object>();
     }
     
+    public boolean isEmpty() {
+        if (!super.isEmpty()) return false;
+        return this.offstack.isEmpty();
+    }
+    
     public int size() {
         return super.size() + this.offstack.size();
     }
@@ -68,7 +73,7 @@ public class SortStore<E> extends SortStack<E> {
         super.push(element, weight);
         this.largest = Math.max(this.largest, weight.longValue());
         if (this.maxsize <= 0) return;
-        while ((super.size() > 0) && (this.size() > this.maxsize)) {
+        while (!super.isEmpty() && this.size() > this.maxsize) {
             this.pop();
         }
     }
@@ -120,7 +125,7 @@ public class SortStore<E> extends SortStack<E> {
     public ArrayList<stackElement> list(final int count) {
         if (count < 0) {
             // shift all elements
-            while (super.size() > 0) this.pop();
+            while (!super.isEmpty()) this.pop();
             return this.offstack;
         }
         if (count > super.size() + this.offstack.size()) throw new RuntimeException("list(" + count + ") exceeded avaiable number of elements (" + size() + ")"); 
diff --git a/source/net/yacy/kelondro/workflow/WorkflowProcessor.java b/source/net/yacy/kelondro/workflow/WorkflowProcessor.java
index 67d66e2ee..87bb9a275 100644
--- a/source/net/yacy/kelondro/workflow/WorkflowProcessor.java
+++ b/source/net/yacy/kelondro/workflow/WorkflowProcessor.java
@@ -85,6 +85,10 @@ public class WorkflowProcessor<J extends WorkflowJob> {
         return this.input.size();
     }
     
+    public boolean queueIsEmpty() {
+        return this.input.isEmpty();
+    }
+    
     public int queueSizeMax() {
         return this.input.size() + this.input.remainingCapacity();
     }
@@ -116,11 +120,11 @@ public class WorkflowProcessor<J extends WorkflowJob> {
     }
     
     public synchronized void relaxCapacity() {
-        if (this.input.size() == 0) return;
+        if (this.input.isEmpty()) return;
         if (this.input.remainingCapacity() > 1000) return;
         BlockingQueue<J> i = new LinkedBlockingQueue<J>();
         J e;
-        while (this.input.size() > 0) {
+        while (!this.input.isEmpty()) {
             e = this.input.poll();
             if (e == null) break;
             i.add(e);
diff --git a/source/net/yacy/repository/Blacklist.java b/source/net/yacy/repository/Blacklist.java
index 28a7f65cd..c2d4ef03f 100644
--- a/source/net/yacy/repository/Blacklist.java
+++ b/source/net/yacy/repository/Blacklist.java
@@ -219,14 +219,14 @@ public class Blacklist {
         ArrayList<String> hostList = blacklistMap.get(host);
         if(hostList != null) {
             hostList.remove(path);
-            if (hostList.size() == 0)
+            if (hostList.isEmpty())
                 blacklistMap.remove(host);
         }
         final HashMap<String, ArrayList<String>> blacklistMapNotMatch = getBlacklistMap(blacklistType,false);
         hostList = blacklistMapNotMatch.get(host);
         if (hostList != null) {
             hostList.remove(path);
-            if (hostList.size() == 0)
+            if (hostList.isEmpty())
                 blacklistMapNotMatch.remove(host);
         }
     }
@@ -462,7 +462,7 @@ public class Blacklist {
     
     public static final String defaultBlacklist(final File listsPath) {
         List<String> dirlist = FileUtils.getDirListing(listsPath, Blacklist.BLACKLIST_FILENAME_FILTER);
-        if (dirlist.size() == 0) return null;
+        if (dirlist.isEmpty()) return null;
         return dirlist.get(0);
     }
 
diff --git a/source/net/yacy/yacy.java b/source/net/yacy/yacy.java
index a68268d54..c4bfacf2e 100644
--- a/source/net/yacy/yacy.java
+++ b/source/net/yacy/yacy.java
@@ -787,7 +787,7 @@ public final class yacy {
             if (wordset.size() != count) {
                 count = count - wordset.size();
                 final BufferedWriter bw = new BufferedWriter(new PrintWriter(new FileWriter(wordlist)));
-                while (wordset.size() > 0) {
+                while (!wordset.isEmpty()) {
                     word = wordset.first();
                     bw.write(word + "\n");
                     wordset.remove(word);