added a gc to cleanup process (once every 10 minutes)

source/net/yacy/search/Switchboard.java

@@ -422,7 +422,6 @@ public final class Switchboard extends serverSwitch {
         CollectionConfiguration.UNIQUE_HEURISTIC_PREFER_HTTPS = this.getConfigBool("search.ranking.uniqueheuristic.preferhttps", false);
         CollectionConfiguration.UNIQUE_HEURISTIC_PREFER_WWWPREFIX = this.getConfigBool("search.ranking.uniqueheuristic.preferwwwprefix", true);
 
-        
         // init libraries
         this.log.config("initializing libraries");
         new Thread("LibraryProvider.initialize") {
@@ -994,7 +993,6 @@ public final class Switchboard extends serverSwitch {
             }
         }.start();
 
-
         // initializing the stackCrawlThread
         this.crawlStacker =
             new CrawlStacker(
@@ -2951,6 +2949,9 @@ public final class Switchboard extends serverSwitch {
             // show deadlocks if there are any in the log
             if (Memory.deadlocks() > 0) Memory.logDeadlocks();
 
+            // clean up
+            System.gc();
+
             return true;
         } catch (final InterruptedException e ) {
             this.log.info("cleanupJob: Shutdown detected");
@@ -3093,7 +3094,6 @@ public final class Switchboard extends serverSwitch {
         }
         final long parsingEndTime = System.currentTimeMillis();
 
-        
         // put anchors on crawl stack
         final long stackStartTime = System.currentTimeMillis();
         // check if the documents have valid urls; this is not a bug patch; it is possible that
@@ -3151,7 +3151,6 @@ public final class Switchboard extends serverSwitch {
                         || response.profile().isCrawlerAlwaysCheckMediaType() /* the crawler must always load resources to double-check the actual Media Type even on unsupported file extensions */;
 
                 /* Handle media links */
-    			
                 for (Map.Entry<DigestURL, String> entry : Document.getImagelinks(documents).entrySet()) {
                     if (addAllLinksToCrawlStack
                             || (response.profile().indexMedia() && TextParser.supportsExtension(entry.getKey()) == null)) {