diff --git a/core/net/src/test/java/org/onosproject/cluster/impl/MastershipManagerTest.java b/core/net/src/test/java/org/onosproject/cluster/impl/MastershipManagerTest.java
index dfde09f..52ee04f 100644
--- a/core/net/src/test/java/org/onosproject/cluster/impl/MastershipManagerTest.java
+++ b/core/net/src/test/java/org/onosproject/cluster/impl/MastershipManagerTest.java
@@ -20,10 +20,10 @@
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
-import org.onosproject.cluster.ClusterEventListener;
+import org.onlab.packet.IpAddress;
 import org.onosproject.cluster.ClusterService;
+import org.onosproject.cluster.ClusterServiceAdapter;
 import org.onosproject.cluster.ControllerNode;
-import org.onosproject.cluster.ControllerNode.State;
 import org.onosproject.cluster.DefaultControllerNode;
 import org.onosproject.cluster.NodeId;
 import org.onosproject.event.impl.TestEventDispatcher;
@@ -32,13 +32,14 @@
 import org.onosproject.mastership.MastershipTermService;
 import org.onosproject.net.DeviceId;
 import org.onosproject.store.trivial.impl.SimpleMastershipStore;
-import org.onlab.packet.IpAddress;
 
 import com.google.common.collect.Sets;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
-import static org.onosproject.net.MastershipRole.*;
+import static org.onosproject.net.MastershipRole.MASTER;
+import static org.onosproject.net.MastershipRole.NONE;
+import static org.onosproject.net.MastershipRole.STANDBY;
 
 /**
  * Test codifying the mastership service contracts.
@@ -151,7 +152,7 @@
         assertEquals("inconsistent terms: ", 3, ts.getMastershipTerm(DEV_MASTER).termNumber());
     }
 
-    private final class TestClusterService implements ClusterService {
+    private final class TestClusterService extends ClusterServiceAdapter {
 
         ControllerNode local = new DefaultControllerNode(NID_LOCAL, LOCALHOST);
 
@@ -165,24 +166,6 @@
             return Sets.newHashSet();
         }
 
-        @Override
-        public ControllerNode getNode(NodeId nodeId) {
-            return null;
-        }
-
-        @Override
-        public State getState(NodeId nodeId) {
-            return null;
-        }
-
-        @Override
-        public void addListener(ClusterEventListener listener) {
-        }
-
-        @Override
-        public void removeListener(ClusterEventListener listener) {
-        }
-
     }
 
     private final class TestSimpleMastershipStore extends SimpleMastershipStore
diff --git a/core/net/src/test/java/org/onosproject/core/impl/TestCoreManager.java b/core/net/src/test/java/org/onosproject/core/impl/TestCoreManager.java
index 1b4765c..13a072f 100644
--- a/core/net/src/test/java/org/onosproject/core/impl/TestCoreManager.java
+++ b/core/net/src/test/java/org/onosproject/core/impl/TestCoreManager.java
@@ -15,42 +15,15 @@
  */
 package org.onosproject.core.impl;
 
-import org.onosproject.core.ApplicationId;
-import org.onosproject.core.CoreService;
+import org.onosproject.core.CoreServiceAdapter;
 import org.onosproject.core.IdGenerator;
-import org.onosproject.core.Version;
 
-import java.util.Set;
-
-public class TestCoreManager implements CoreService {
-    @Override
-    public Version version() {
-        return null;
-    }
-
-    @Override
-    public Set<ApplicationId> getAppIds() {
-        return null;
-    }
-
-    @Override
-     public ApplicationId getAppId(Short id) {
-        return null;
-    }
-
-    @Override
-    public ApplicationId getAppId(String name) {
-        return null;
-    }
-
-    @Override
-    public ApplicationId registerApplication(String identifier) {
-        return null;
-    }
+public class TestCoreManager extends CoreServiceAdapter {
 
     @Override
     public IdGenerator getIdGenerator(String topic) {
         IdBlockAllocator idBlockAllocator = new DummyIdBlockAllocator();
         return new BlockAllocatorBasedIdGenerator(idBlockAllocator);
     }
+
 }
diff --git a/core/net/src/test/java/org/onosproject/net/device/impl/DeviceManagerTest.java b/core/net/src/test/java/org/onosproject/net/device/impl/DeviceManagerTest.java
index 0956fd6..ca8aa34 100644
--- a/core/net/src/test/java/org/onosproject/net/device/impl/DeviceManagerTest.java
+++ b/core/net/src/test/java/org/onosproject/net/device/impl/DeviceManagerTest.java
@@ -15,17 +15,20 @@
  */
 package org.onosproject.net.device.impl;
 
-import com.google.common.collect.Sets;
+import java.util.ArrayList;
+import java.util.Iterator;
+import java.util.List;
+import java.util.Set;
 
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
-import org.onosproject.cluster.ClusterEventListener;
-import org.onosproject.cluster.ClusterService;
+import org.onlab.packet.ChassisId;
+import org.onlab.packet.IpAddress;
+import org.onosproject.cluster.ClusterServiceAdapter;
 import org.onosproject.cluster.ControllerNode;
 import org.onosproject.cluster.DefaultControllerNode;
 import org.onosproject.cluster.NodeId;
-import org.onosproject.cluster.ControllerNode.State;
 import org.onosproject.event.Event;
 import org.onosproject.event.impl.TestEventDispatcher;
 import org.onosproject.mastership.MastershipServiceAdapter;
@@ -51,18 +54,22 @@
 import org.onosproject.net.provider.AbstractProvider;
 import org.onosproject.net.provider.ProviderId;
 import org.onosproject.store.trivial.impl.SimpleDeviceStore;
-import org.onlab.packet.ChassisId;
-import org.onlab.packet.IpAddress;
 
-import java.util.ArrayList;
-import java.util.Iterator;
-import java.util.List;
-import java.util.Set;
+import com.google.common.collect.Sets;
 
-import static org.junit.Assert.*;
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 import static org.onosproject.net.Device.Type.SWITCH;
 import static org.onosproject.net.DeviceId.deviceId;
-import static org.onosproject.net.device.DeviceEvent.Type.*;
+import static org.onosproject.net.device.DeviceEvent.Type.DEVICE_ADDED;
+import static org.onosproject.net.device.DeviceEvent.Type.DEVICE_AVAILABILITY_CHANGED;
+import static org.onosproject.net.device.DeviceEvent.Type.DEVICE_UPDATED;
+import static org.onosproject.net.device.DeviceEvent.Type.PORT_ADDED;
+import static org.onosproject.net.device.DeviceEvent.Type.PORT_REMOVED;
+import static org.onosproject.net.device.DeviceEvent.Type.PORT_UPDATED;
 
 /**
  * Test codifying the device service & device provider service contracts.
@@ -310,7 +317,7 @@
     }
 
     // code clone
-    private final class TestClusterService implements ClusterService {
+    private final class TestClusterService extends ClusterServiceAdapter {
 
         ControllerNode local = new DefaultControllerNode(NID_LOCAL, LOCALHOST);
 
@@ -319,28 +326,6 @@
             return local;
         }
 
-        @Override
-        public Set<ControllerNode> getNodes() {
-            return null;
-        }
-
-        @Override
-        public ControllerNode getNode(NodeId nodeId) {
-            return null;
-        }
-
-        @Override
-        public State getState(NodeId nodeId) {
-            return null;
-        }
-
-        @Override
-        public void addListener(ClusterEventListener listener) {
-        }
-
-        @Override
-        public void removeListener(ClusterEventListener listener) {
-        }
     }
 
     private final class TestClockProviderService implements
diff --git a/core/net/src/test/java/org/onosproject/net/flow/impl/FlowRuleManagerTest.java b/core/net/src/test/java/org/onosproject/net/flow/impl/FlowRuleManagerTest.java
index f7d7287..a22dd08 100644
--- a/core/net/src/test/java/org/onosproject/net/flow/impl/FlowRuleManagerTest.java
+++ b/core/net/src/test/java/org/onosproject/net/flow/impl/FlowRuleManagerTest.java
@@ -32,10 +32,9 @@
 import org.junit.Before;
 import org.junit.Test;
 import org.onosproject.core.ApplicationId;
-import org.onosproject.core.CoreService;
+import org.onosproject.core.CoreServiceAdapter;
 import org.onosproject.core.DefaultApplicationId;
 import org.onosproject.core.IdGenerator;
-import org.onosproject.core.Version;
 import org.onosproject.event.impl.TestEventDispatcher;
 import org.onosproject.net.DefaultDevice;
 import org.onosproject.net.Device;
@@ -219,14 +218,14 @@
         FlowRule r3 = flowRule(3, 3);
 
         assertTrue("store should be empty",
-                   Sets.newHashSet(service.getFlowEntries(DID)).isEmpty());
+                Sets.newHashSet(service.getFlowEntries(DID)).isEmpty());
         mgr.applyFlowRules(r1, r2, r3);
         assertEquals("3 rules should exist", 3, flowCount());
         assertTrue("Entries should be pending add.",
-                   validateState(ImmutableMap.of(
-                           r1, FlowEntryState.PENDING_ADD,
-                           r2, FlowEntryState.PENDING_ADD,
-                           r3, FlowEntryState.PENDING_ADD)));
+                validateState(ImmutableMap.of(
+                        r1, FlowEntryState.PENDING_ADD,
+                        r2, FlowEntryState.PENDING_ADD,
+                        r3, FlowEntryState.PENDING_ADD)));
     }
 
     @Test
@@ -248,10 +247,10 @@
         validateEvents(RULE_REMOVE_REQUESTED, RULE_REMOVE_REQUESTED);
         assertEquals("3 rule should exist", 3, flowCount());
         assertTrue("Entries should be pending remove.",
-                   validateState(ImmutableMap.of(
-                           f1, FlowEntryState.PENDING_REMOVE,
-                           f2, FlowEntryState.PENDING_REMOVE,
-                           f3, FlowEntryState.ADDED)));
+                validateState(ImmutableMap.of(
+                        f1, FlowEntryState.PENDING_REMOVE,
+                        f2, FlowEntryState.PENDING_REMOVE,
+                        f3, FlowEntryState.ADDED)));
 
         mgr.removeFlowRules(f1);
         assertEquals("3 rule should still exist", 3, flowCount());
@@ -277,7 +276,7 @@
 
 
         validateEvents(RULE_ADD_REQUESTED, RULE_ADD_REQUESTED, RULE_ADDED,
-                       RULE_ADDED, RULE_REMOVE_REQUESTED, RULE_REMOVED);
+                RULE_ADDED, RULE_REMOVE_REQUESTED, RULE_REMOVED);
 
         providerService.flowRemoved(fe1);
         validateEvents();
@@ -317,7 +316,7 @@
                            f3, FlowEntryState.PENDING_ADD)));
 
         validateEvents(RULE_ADD_REQUESTED, RULE_ADD_REQUESTED, RULE_ADD_REQUESTED,
-                       RULE_ADDED, RULE_ADDED);
+                RULE_ADDED, RULE_ADDED);
     }
 
     @Test
@@ -374,7 +373,7 @@
         mgr.applyFlowRules(f1, f2);
 
         assertTrue("should have two rules",
-                   Lists.newLinkedList(mgr.getFlowRulesById(appId)).size() == 2);
+                Lists.newLinkedList(mgr.getFlowRulesById(appId)).size() == 2);
     }
 
     @Test
@@ -583,31 +582,7 @@
         }
     }
 
-    private class TestCoreService implements CoreService {
-        @Override
-        public Version version() {
-            return null;
-        }
-
-        @Override
-        public Set<ApplicationId> getAppIds() {
-            return null;
-        }
-
-        @Override
-        public ApplicationId getAppId(Short id) {
-            return null;
-        }
-
-        @Override
-        public ApplicationId getAppId(String name) {
-            return null;
-        }
-
-        @Override
-        public ApplicationId registerApplication(String identifier) {
-            return null;
-        }
+    private class TestCoreService extends CoreServiceAdapter {
 
         @Override
         public IdGenerator getIdGenerator(String topic) {
diff --git a/core/net/src/test/java/org/onosproject/net/intent/impl/MockFlowRuleService.java b/core/net/src/test/java/org/onosproject/net/intent/impl/MockFlowRuleService.java
index 66ea27e..27e523d 100644
--- a/core/net/src/test/java/org/onosproject/net/intent/impl/MockFlowRuleService.java
+++ b/core/net/src/test/java/org/onosproject/net/intent/impl/MockFlowRuleService.java
@@ -23,14 +23,13 @@
 import org.onosproject.net.flow.DefaultFlowEntry;
 import org.onosproject.net.flow.FlowEntry;
 import org.onosproject.net.flow.FlowRule;
-import org.onosproject.net.flow.FlowRuleListener;
 import org.onosproject.net.flow.FlowRuleOperations;
-import org.onosproject.net.flow.FlowRuleService;
+import org.onosproject.net.flow.FlowRuleServiceAdapter;
 
 import com.google.common.collect.Sets;
 
 
-public class MockFlowRuleService implements FlowRuleService {
+public class MockFlowRuleService extends FlowRuleServiceAdapter {
 
     final Set<FlowRule> flows = Sets.newHashSet();
     boolean success;
@@ -62,16 +61,6 @@
     }
 
     @Override
-    public void addListener(FlowRuleListener listener) {
-        //TODO not implemented
-    }
-
-    @Override
-    public void removeListener(FlowRuleListener listener) {
-        //TODO not implemented
-    }
-
-    @Override
     public int getFlowRuleCount() {
         return flows.size();
     }
@@ -99,11 +88,6 @@
     }
 
     @Override
-    public void removeFlowRulesById(ApplicationId appId) {
-        //TODO not implemented
-    }
-
-    @Override
     public Iterable<FlowRule> getFlowRulesById(ApplicationId id) {
         return flows.stream()
                     .filter(flow -> flow.appId() == id.id())
diff --git a/core/store/dist/src/test/java/org/onosproject/store/cluster/StaticClusterService.java b/core/store/dist/src/test/java/org/onosproject/store/cluster/StaticClusterService.java
index 8eb06b8..a14e98d 100644
--- a/core/store/dist/src/test/java/org/onosproject/store/cluster/StaticClusterService.java
+++ b/core/store/dist/src/test/java/org/onosproject/store/cluster/StaticClusterService.java
@@ -19,15 +19,14 @@
 import java.util.Map;
 import java.util.Set;
 
-import org.onosproject.cluster.ClusterEventListener;
-import org.onosproject.cluster.ClusterService;
+import org.onosproject.cluster.ClusterServiceAdapter;
 import org.onosproject.cluster.ControllerNode;
-import org.onosproject.cluster.NodeId;
 import org.onosproject.cluster.ControllerNode.State;
+import org.onosproject.cluster.NodeId;
 
 import com.google.common.collect.Sets;
 
-public abstract class StaticClusterService implements ClusterService {
+public abstract class StaticClusterService extends ClusterServiceAdapter {
 
     protected final Map<NodeId, ControllerNode> nodes = new HashMap<>();
     protected final Map<NodeId, ControllerNode.State> nodeStates = new HashMap<>();
@@ -53,11 +52,4 @@
         return nodeStates.get(nodeId);
     }
 
-    @Override
-    public void addListener(ClusterEventListener listener) {
-    }
-
-    @Override
-    public void removeListener(ClusterEventListener listener) {
-    }
 }
diff --git a/core/store/dist/src/test/java/org/onosproject/store/mastership/impl/DistributedMastershipStoreTest.java b/core/store/dist/src/test/java/org/onosproject/store/mastership/impl/DistributedMastershipStoreTest.java
index 1a96161..d3247ec 100644
--- a/core/store/dist/src/test/java/org/onosproject/store/mastership/impl/DistributedMastershipStoreTest.java
+++ b/core/store/dist/src/test/java/org/onosproject/store/mastership/impl/DistributedMastershipStoreTest.java
@@ -15,10 +15,6 @@
  */
 package org.onosproject.store.mastership.impl;
 
-import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
-import static org.junit.Assert.assertTrue;
-import static org.onosproject.net.MastershipRole.*;
 import java.util.Map;
 import java.util.Set;
 import java.util.concurrent.CountDownLatch;
@@ -30,26 +26,31 @@
 import org.junit.BeforeClass;
 import org.junit.Ignore;
 import org.junit.Test;
-import org.onosproject.cluster.ClusterEventListener;
-import org.onosproject.cluster.ClusterService;
+import org.onlab.packet.IpAddress;
+import org.onosproject.cluster.ClusterServiceAdapter;
 import org.onosproject.cluster.ControllerNode;
-import org.onosproject.cluster.ControllerNode.State;
 import org.onosproject.cluster.DefaultControllerNode;
 import org.onosproject.cluster.NodeId;
 import org.onosproject.mastership.MastershipEvent;
+import org.onosproject.mastership.MastershipEvent.Type;
 import org.onosproject.mastership.MastershipStoreDelegate;
 import org.onosproject.mastership.MastershipTerm;
-import org.onosproject.mastership.MastershipEvent.Type;
 import org.onosproject.net.DeviceId;
 import org.onosproject.net.MastershipRole;
 import org.onosproject.store.hz.StoreManager;
 import org.onosproject.store.hz.StoreService;
 import org.onosproject.store.hz.TestStoreManager;
 import org.onosproject.store.serializers.KryoSerializer;
-import org.onlab.packet.IpAddress;
 
 import com.google.common.collect.Sets;
 
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.onosproject.net.MastershipRole.MASTER;
+import static org.onosproject.net.MastershipRole.NONE;
+import static org.onosproject.net.MastershipRole.STANDBY;
+
 /**
  * Test of the Hazelcast-based distributed MastershipStore implementation.
  */
@@ -300,7 +301,7 @@
         }
     }
 
-    private class TestClusterService implements ClusterService {
+    private class TestClusterService extends ClusterServiceAdapter {
 
         protected ControllerNode current;
 
@@ -314,24 +315,6 @@
             return Sets.newHashSet(CN1, CN2);
         }
 
-        @Override
-        public ControllerNode getNode(NodeId nodeId) {
-            return null;
-        }
-
-        @Override
-        public State getState(NodeId nodeId) {
-            return null;
-        }
-
-        @Override
-        public void addListener(ClusterEventListener listener) {
-        }
-
-        @Override
-        public void removeListener(ClusterEventListener listener) {
-        }
-
     }
 
 }