We need to synchronize some toString methods since they access some data structures that cannot be modified concurrently

src/kademlia/core/DefaultConfiguration.java

@@ -14,7 +14,7 @@ public class DefaultConfiguration implements KadConfiguration
     private final static long RESPONSE_TIMEOUT = 1500;
     private final static long OPERATION_TIMEOUT = 3000;
     private final static int CONCURRENCY = 10;
-    private final static int K = 4;
+    private final static int K = 10;
     private final static int RCSIZE = 3;
     private final static int STALE = 1;
     private final static String LOCAL_FOLDER = "kademlia";

src/kademlia/dht/DHT.java

@@ -319,7 +319,7 @@ public class DHT
     }
 
     @Override
-    public String toString()
+    public synchronized String toString()
     {
         return this.entriesManager.toString();
     }

src/kademlia/dht/StoredContentManager.java

@@ -176,7 +176,7 @@ class StoredContentManager
     }
 
     @Override
-    public String toString()
+    public synchronized String toString()
     {
         StringBuilder sb = new StringBuilder("Stored Content: \n");
         for (List<StorageEntryMetadata> es : this.entries.values())