diff --git a/plugins/event-bus/inmemory/src/org/apache/cloudstack/mom/inmemory/InMemoryEventBus.java b/plugins/event-bus/inmemory/src/org/apache/cloudstack/mom/inmemory/InMemoryEventBus.java
index 9a57ff067bf..fd2f9f357f3 100644
--- a/plugins/event-bus/inmemory/src/org/apache/cloudstack/mom/inmemory/InMemoryEventBus.java
+++ b/plugins/event-bus/inmemory/src/org/apache/cloudstack/mom/inmemory/InMemoryEventBus.java
@@ -26,12 +26,13 @@ import java.util.concurrent.ConcurrentHashMap;
 import javax.ejb.Local;
 import javax.naming.ConfigurationException;
 
+import org.apache.log4j.Logger;
+
 import org.apache.cloudstack.framework.events.Event;
 import org.apache.cloudstack.framework.events.EventBus;
 import org.apache.cloudstack.framework.events.EventBusException;
 import org.apache.cloudstack.framework.events.EventSubscriber;
 import org.apache.cloudstack.framework.events.EventTopic;
-import org.apache.log4j.Logger;
 
 import com.cloud.utils.Pair;
 import com.cloud.utils.component.ManagerBase;
@@ -41,7 +42,7 @@ public class InMemoryEventBus extends ManagerBase implements EventBus {
 
     private static final Logger s_logger = Logger.getLogger(InMemoryEventBus.class);
 
-    private final static ConcurrentHashMap<UUID, Pair<EventTopic, EventSubscriber>> subscribers;
+    private final static Map<UUID, Pair<EventTopic, EventSubscriber>> subscribers;
 
     static {
         subscribers = new ConcurrentHashMap<UUID, Pair<EventTopic, EventSubscriber>>();
diff --git a/utils/src/com/cloud/utils/backoff/impl/ConstantTimeBackoff.java b/utils/src/com/cloud/utils/backoff/impl/ConstantTimeBackoff.java
index 24d4d111c33..14eae16e793 100755
--- a/utils/src/com/cloud/utils/backoff/impl/ConstantTimeBackoff.java
+++ b/utils/src/com/cloud/utils/backoff/impl/ConstantTimeBackoff.java
@@ -45,7 +45,7 @@ import com.cloud.utils.component.AdapterBase;
 @Local(value = {BackoffAlgorithm.class})
 public class ConstantTimeBackoff extends AdapterBase implements BackoffAlgorithm, ConstantTimeBackoffMBean {
     long _time;
-    private final ConcurrentHashMap<String, Thread> _asleep = new ConcurrentHashMap<String, Thread>();
+    private final Map<String, Thread> _asleep = new ConcurrentHashMap<String, Thread>();
     private final static Log LOG = LogFactory.getLog(ConstantTimeBackoff.class);
 
     @Override