diff --git a/ethereumj-core/src/main/java/org/ethereum/facade/EthereumImpl.java b/ethereumj-core/src/main/java/org/ethereum/facade/EthereumImpl.java
index a01b2685..57c343eb 100644
--- a/ethereumj-core/src/main/java/org/ethereum/facade/EthereumImpl.java
+++ b/ethereumj-core/src/main/java/org/ethereum/facade/EthereumImpl.java
@@ -100,16 +100,6 @@ public class EthereumImpl implements Ethereum {
         WorldManager.getInstance().addListener(listener);
     }
 
-
-    private void sleep10Milli(){
-        try {
-            Thread.sleep(10);
-        } catch (InterruptedException e) {
-            e.printStackTrace();
-        }
-    }
-
-
     @Override
     public void loadBlockChain() {
         WorldManager.getInstance().loadBlockchain();
diff --git a/ethereumj-core/src/main/java/org/ethereum/gui/PeersTableModel.java b/ethereumj-core/src/main/java/org/ethereum/gui/PeersTableModel.java
index 438d6278..1dcc51ee 100644
--- a/ethereumj-core/src/main/java/org/ethereum/gui/PeersTableModel.java
+++ b/ethereumj-core/src/main/java/org/ethereum/gui/PeersTableModel.java
@@ -111,7 +111,7 @@ public class PeersTableModel extends AbstractTableModel {
         synchronized (peerInfoList) {
             peerInfoList.clear();
 
-            final Collection<PeerData> peers = WorldManager.getInstance().getPeers();
+            final Queue<PeerData> peers = WorldManager.getInstance().getPeers();
             for (PeerData peer : peers) {
                 InetAddress addr = peer.getInetAddress();
                 Location cr = IpGeoDB.getLocationForIp(addr);
diff --git a/ethereumj-core/src/main/java/org/ethereum/net/client/ClientPeer.java b/ethereumj-core/src/main/java/org/ethereum/net/client/ClientPeer.java
index c6174e30..67447eee 100644
--- a/ethereumj-core/src/main/java/org/ethereum/net/client/ClientPeer.java
+++ b/ethereumj-core/src/main/java/org/ethereum/net/client/ClientPeer.java
@@ -16,9 +16,11 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.spongycastle.util.encoders.Hex;
 
+import java.util.AbstractQueue;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.List;
+import java.util.Queue;
 import java.util.concurrent.TimeUnit;
 
 import static org.ethereum.config.SystemProperties.CONFIG;
@@ -87,7 +89,7 @@ public class ClientPeer {
 
             handler.killTimers();
 
-            final Collection<PeerData> peers =  WorldManager.getInstance().getPeers();
+            final Queue<PeerData> peers =  WorldManager.getInstance().getPeers();
 
             for (PeerData peer : peers){
                 if (host.equals(peer.getInetAddress().getHostAddress()) &&
diff --git a/ethereumj-core/src/main/java/org/ethereum/net/peerdiscovery/PeerDiscovery.java b/ethereumj-core/src/main/java/org/ethereum/net/peerdiscovery/PeerDiscovery.java
index 718295a3..f75ccc82 100644
--- a/ethereumj-core/src/main/java/org/ethereum/net/peerdiscovery/PeerDiscovery.java
+++ b/ethereumj-core/src/main/java/org/ethereum/net/peerdiscovery/PeerDiscovery.java
@@ -6,6 +6,7 @@ import org.slf4j.LoggerFactory;
 
 import java.util.Collection;
 import java.util.List;
+import java.util.Queue;
 import java.util.concurrent.*;
 import java.util.concurrent.atomic.AtomicBoolean;
 
@@ -25,11 +26,11 @@ public class PeerDiscovery {
     private ThreadPoolExecutor executorPool;
     private PeerDiscoveryMonitorThread monitor;
     
-    private final Collection<PeerData> peers;
+    private final Queue<PeerData> peers;
 
     private final AtomicBoolean started = new AtomicBoolean(false);
 
-    public PeerDiscovery(Collection<PeerData> peers) {
+    public PeerDiscovery(Queue<PeerData> peers) {
         this.peers = peers;
     }
 
diff --git a/ethereumj-core/src/test/java/org/ethereum/net/MessagesTest.java b/ethereumj-core/src/test/java/org/ethereum/net/MessagesTest.java
index c63351bf..b2f5eee1 100644
--- a/ethereumj-core/src/test/java/org/ethereum/net/MessagesTest.java
+++ b/ethereumj-core/src/test/java/org/ethereum/net/MessagesTest.java
@@ -122,7 +122,8 @@ public class MessagesTest {
 
         assertEquals(2, peersMessage.getPeers().size());
 
-        PeerData peerData = peersMessage.getPeers().iterator().next();
+        Iterator<PeerData> it = peersMessage.getPeers().iterator(); it.next();
+        PeerData peerData = it.next();
 
         assertEquals("/81.99.225.18", peerData.getInetAddress().toString());
         assertEquals(30303, peerData.getPort());