diff --git a/htroot/Network.java b/htroot/Network.java
index bdc545348..9ec7a158d 100644
--- a/htroot/Network.java
+++ b/htroot/Network.java
@@ -31,6 +31,7 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.regex.PatternSyntaxException;
@@ -180,10 +181,10 @@ public class Network {
                     return prop;
                 }
 
-                final HashMap<String, String> map = new HashMap<String, String>();
+                final ConcurrentHashMap<String, String> map = new ConcurrentHashMap<String, String>();
                 map.put(yacySeed.IP, post.get("peerIP"));
                 map.put(yacySeed.PORT, post.get("peerPort"));
-                yacySeed peer = new yacySeed(post.get("peerHash"),map);
+                yacySeed peer = new yacySeed(post.get("peerHash"), map);
 
                 sb.updateMySeed();
                 final int added = yacyClient.publishMySeed(sb.peers.mySeed(), sb.peers.peerActions, peer.getPublicAddress(), peer.hash);
diff --git a/source/de/anomic/yacy/yacySeed.java b/source/de/anomic/yacy/yacySeed.java
index c5cc1d6ee..55bff6454 100644
--- a/source/de/anomic/yacy/yacySeed.java
+++ b/source/de/anomic/yacy/yacySeed.java
@@ -55,6 +55,7 @@ import java.util.Random;
 import java.util.Set;
 import java.util.TreeMap;
 import java.util.TreeSet;
+import java.util.concurrent.ConcurrentHashMap;
 
 import net.yacy.kelondro.data.word.Word;
 import net.yacy.kelondro.order.Base64Order;
@@ -169,12 +170,12 @@ public class yacySeed implements Cloneable {
     /** the peer-hash */
     public String hash;
     /** a set of identity founding values, eg. IP, name of the peer, YaCy-version, ...*/
-    private final Map<String, String> dna;
+    private final ConcurrentHashMap<String, String> dna;
     public int available;
     public int selectscore = -1; // only for debugging
     public String alternativeIP = null;
 
-    public yacySeed(final String theHash, final Map<String, String> theDna) {
+    public yacySeed(final String theHash, final ConcurrentHashMap<String, String> theDna) {
         // create a seed with a pre-defined hash map
         assert theHash != null;
         this.hash = theHash;
@@ -186,7 +187,7 @@ public class yacySeed implements Cloneable {
     }
 
     public yacySeed(final String theHash) {
-        this.dna = new HashMap<String, String>();
+        this.dna = new ConcurrentHashMap<String, String>();
 
         // settings that can only be computed by originating peer:
         // at first startup -
@@ -776,7 +777,7 @@ public class yacySeed implements Cloneable {
         if (seed == null) { return null; }
         
         // extract hash
-        final HashMap<String, String> dna = MapTools.string2map(seed, ",");
+        final ConcurrentHashMap<String, String> dna = MapTools.string2map(seed, ",");
         final String hash = dna.remove(yacySeed.HASH);
         if (hash == null) return null;
         final yacySeed resultSeed = new yacySeed(hash, dna);
@@ -881,11 +882,10 @@ public class yacySeed implements Cloneable {
         return mySeed;
     }
 
-    @SuppressWarnings("unchecked")
     public final yacySeed clone() {
-        synchronized (this.dna) {
-            return new yacySeed(this.hash, (HashMap<String, String>) (new HashMap<String, String>(this.dna).clone()));
-        }
+        ConcurrentHashMap<String, String> ndna = new ConcurrentHashMap<String, String>();
+        ndna.putAll(this.dna);
+        return new yacySeed(this.hash, ndna);
     }
     
 }
diff --git a/source/de/anomic/yacy/yacySeedDB.java b/source/de/anomic/yacy/yacySeedDB.java
index d4c77b5a9..bfa6f050b 100644
--- a/source/de/anomic/yacy/yacySeedDB.java
+++ b/source/de/anomic/yacy/yacySeedDB.java
@@ -38,6 +38,7 @@ import java.util.Hashtable;
 import java.util.Iterator;
 import java.util.Map;
 import java.util.TreeMap;
+import java.util.concurrent.ConcurrentHashMap;
 
 import net.yacy.kelondro.blob.MapDataMining;
 import net.yacy.kelondro.data.meta.DigestURI;
@@ -529,9 +530,9 @@ public final class yacySeedDB implements AlternativeDomainNames {
     private yacySeed get(final String hash, final MapDataMining database) {
         if (hash == null) return null;
         if ((this.mySeed != null) && (hash.equals(mySeed.hash))) return mySeed;
-        Map<String, String> entry;
+        ConcurrentHashMap<String, String> entry = new ConcurrentHashMap<String, String>();
         try {
-            entry = database.get(hash);
+            entry.putAll(database.get(hash));
         } catch (final IOException e) {
             entry = null;
         }
@@ -982,9 +983,10 @@ public final class yacySeedDB implements AlternativeDomainNames {
         public yacySeed internalNext() {
             if ((it == null) || (!(it.hasNext()))) return null;
             try {
-                Map<String, String> dna;
+                ConcurrentHashMap<String, String> dna;
                 while (it.hasNext()) {
-                    dna = it.next();
+                    dna = new ConcurrentHashMap<String, String>();
+                    dna.putAll(it.next());
                     assert dna != null;
                     if (dna == null) continue;
                     final String hash = dna.remove("key");
diff --git a/source/net/yacy/kelondro/util/MapTools.java b/source/net/yacy/kelondro/util/MapTools.java
index 3a3f65a29..3906784ea 100644
--- a/source/net/yacy/kelondro/util/MapTools.java
+++ b/source/net/yacy/kelondro/util/MapTools.java
@@ -27,7 +27,6 @@ package net.yacy.kelondro.util;
 
 import java.util.Collections;
 import java.util.ConcurrentModificationException;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
 import java.util.Map;
@@ -35,6 +34,7 @@ import java.util.Properties;
 import java.util.Set;
 import java.util.StringTokenizer;
 import java.util.Map.Entry;
+import java.util.concurrent.ConcurrentHashMap;
 
 public final class MapTools {
 
@@ -51,10 +51,10 @@ public final class MapTools {
         return p;
     }
     
-    public static HashMap<String, String> string2map(String string, final String separator) {
+    public static ConcurrentHashMap<String, String> string2map(String string, final String separator) {
         // this can be used to parse a Map.toString() into a Map again
         if (string == null) return null;
-        final HashMap<String, String> map = new HashMap<String, String>();
+        final ConcurrentHashMap<String, String> map = new ConcurrentHashMap<String, String>();
         int pos;
         if ((pos = string.indexOf('{')) >= 0) string = string.substring(pos + 1).trim();
         if ((pos = string.lastIndexOf('}')) >= 0) string = string.substring(0, pos).trim();