diff --git a/core/store/src/main/java/org/onlab/onos/store/device/impl/OnosClockService.java b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/OnosClockService.java
similarity index 96%
rename from core/store/src/main/java/org/onlab/onos/store/device/impl/OnosClockService.java
rename to core/store/dist/src/main/java/org/onlab/onos/store/device/impl/OnosClockService.java
index 4046fd0..a99482f 100644
--- a/core/store/src/main/java/org/onlab/onos/store/device/impl/OnosClockService.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/OnosClockService.java
@@ -12,21 +12,21 @@
 import org.apache.felix.scr.annotations.Service;
 import org.onlab.onos.cluster.MastershipTerm;
 import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.store.ClockService;
 import org.onlab.onos.store.Timestamp;
-import org.onlab.onos.store.common.ClockService;
 import org.onlab.onos.store.impl.OnosTimestamp;
 import org.slf4j.Logger;
 
 @Component(immediate = true)
 @Service
 public class OnosClockService implements ClockService {
-    
+
     private final Logger log = getLogger(getClass());
 
     // TODO: Implement per device ticker that is reset to 0 at the beginning of a new term.
     private final AtomicInteger ticker = new AtomicInteger(0);
     private ConcurrentMap<DeviceId, MastershipTerm> deviceMastershipTerms = new ConcurrentHashMap<>();
-    
+
     @Activate
     public void activate() {
         log.info("Started");
@@ -36,7 +36,7 @@
     public void deactivate() {
         log.info("Stopped");
     }
-    
+
     @Override
     public Timestamp getTimestamp(DeviceId deviceId) {
         MastershipTerm term = deviceMastershipTerms.get(deviceId);
diff --git a/core/store/src/main/java/org/onlab/onos/store/device/impl/OnosDistributedDeviceStore.java b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/OnosDistributedDeviceStore.java
similarity index 92%
rename from core/store/src/main/java/org/onlab/onos/store/device/impl/OnosDistributedDeviceStore.java
rename to core/store/dist/src/main/java/org/onlab/onos/store/device/impl/OnosDistributedDeviceStore.java
index 0d79edf..30374c3 100644
--- a/core/store/src/main/java/org/onlab/onos/store/device/impl/OnosDistributedDeviceStore.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/OnosDistributedDeviceStore.java
@@ -1,8 +1,8 @@
 package org.onlab.onos.store.device.impl;
 
 import static com.google.common.base.Predicates.notNull;
+import static com.google.common.base.Preconditions.checkState;
 
-import com.google.common.base.Preconditions;
 import com.google.common.collect.FluentIterable;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.ImmutableSet.Builder;
@@ -25,9 +25,9 @@
 import org.onlab.onos.net.device.DeviceStoreDelegate;
 import org.onlab.onos.net.device.PortDescription;
 import org.onlab.onos.net.provider.ProviderId;
+import org.onlab.onos.store.AbstractStore;
+import org.onlab.onos.store.ClockService;
 import org.onlab.onos.store.Timestamp;
-import org.onlab.onos.store.common.ClockService;
-import org.onlab.onos.store.impl.AbstractDistributedStore;
 import org.slf4j.Logger;
 
 import java.util.ArrayList;
@@ -52,7 +52,7 @@
 @Component(immediate = true)
 @Service
 public class OnosDistributedDeviceStore
-        extends AbstractDistributedStore<DeviceEvent, DeviceStoreDelegate>
+        extends AbstractStore<DeviceEvent, DeviceStoreDelegate>
         implements DeviceStore {
 
     private final Logger log = getLogger(getClass());
@@ -61,21 +61,19 @@
 
     private ConcurrentHashMap<DeviceId, VersionedValue<Device>> devices;
     private ConcurrentHashMap<DeviceId, Map<PortNumber, VersionedValue<Port>>> devicePorts;
-    
+
     @Reference(cardinality = ReferenceCardinality.MANDATORY_UNARY)
     protected ClockService clockService;
 
-    @Override
     @Activate
     public void activate() {
-        super.activate();
 
         devices = new ConcurrentHashMap<>();
         devicePorts = new ConcurrentHashMap<>();
 
         log.info("Started");
     }
-    
+
     @Deactivate
     public void deactivate() {
         log.info("Stopped");
@@ -107,12 +105,13 @@
                                             DeviceDescription deviceDescription) {
         Timestamp now = clockService.getTimestamp(deviceId);
         VersionedValue<Device> device = devices.get(deviceId);
-        
+
         if (device == null) {
             return createDevice(providerId, deviceId, deviceDescription, now);
         }
-        
-        Preconditions.checkState(now.compareTo(device.timestamp()) > 0, "Existing device has a timestamp in the future!");
+
+        checkState(now.compareTo(device.timestamp()) > 0,
+                "Existing device has a timestamp in the future!");
 
         return updateDevice(providerId, device.entity(), deviceDescription, now);
     }
@@ -156,7 +155,8 @@
                 desc.swVersion(),
                 desc.serialNumber());
 
-        VersionedValue<Device> oldDevice = devices.put(device.id(), new VersionedValue<Device>(updated, true, timestamp));
+        VersionedValue<Device> oldDevice = devices.put(device.id(),
+                new VersionedValue<Device>(updated, true, timestamp));
         if (!oldDevice.isUp()) {
             return new DeviceEvent(DEVICE_AVAILABILITY_CHANGED, device, null);
         } else {
@@ -168,21 +168,20 @@
     public DeviceEvent markOffline(DeviceId deviceId) {
         VersionedValue<Device> device = devices.get(deviceId);
         boolean willRemove = device != null && device.isUp();
-        if (!willRemove) return null;
+        if (!willRemove) {
+            return null;
+        }
         Timestamp timestamp = clockService.getTimestamp(deviceId);
-        if (replaceIfLatest(device.entity(), false, timestamp))
-        {
+        if (replaceIfLatest(device.entity(), false, timestamp)) {
             return new DeviceEvent(DEVICE_AVAILABILITY_CHANGED, device.entity(), null);
         }
         return null;
     }
-    
+
     // Replace existing value if its timestamp is older.
-    private synchronized boolean replaceIfLatest(Device device, boolean isUp, Timestamp timestamp)
-    {
+    private synchronized boolean replaceIfLatest(Device device, boolean isUp, Timestamp timestamp) {
         VersionedValue<Device> existingValue = devices.get(device.id());
-        if (timestamp.compareTo(existingValue.timestamp()) > 0)
-        {
+        if (timestamp.compareTo(existingValue.timestamp()) > 0) {
             devices.put(device.id(), new VersionedValue<Device>(device, isUp, timestamp));
             return true;
         }
@@ -203,8 +202,11 @@
             Set<PortNumber> processed = new HashSet<>();
             for (PortDescription portDescription : portDescriptions) {
                 VersionedValue<Port> port = ports.get(portDescription.portNumber());
-                if (port == null) events.add(createPort(device, portDescription, ports, timestamp));
-                Preconditions.checkState(timestamp.compareTo(port.timestamp()) > 0, "Existing port state has a timestamp in the future!");
+                if (port == null) {
+                    events.add(createPort(device, portDescription, ports, timestamp));
+                }
+                checkState(timestamp.compareTo(port.timestamp()) > 0,
+                        "Existing port state has a timestamp in the future!");
                 events.add(updatePort(device, port, portDescription, ports, timestamp));
                 processed.add(portDescription.portNumber());
             }
@@ -304,8 +306,10 @@
     @Override
     public List<Port> getPorts(DeviceId deviceId) {
         Map<PortNumber, VersionedValue<Port>> versionedPorts = devicePorts.get(deviceId);
-        if (versionedPorts == null) return Collections.emptyList();
-        List<Port> ports = new ArrayList<Port>(); 
+        if (versionedPorts == null) {
+            return Collections.emptyList();
+        }
+        List<Port> ports = new ArrayList<>();
         for (VersionedValue<Port> port : versionedPorts.values()) {
             ports.add(port.entity());
         }
diff --git a/core/store/src/main/java/org/onlab/onos/store/device/impl/VersionedValue.java b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/VersionedValue.java
similarity index 92%
rename from core/store/src/main/java/org/onlab/onos/store/device/impl/VersionedValue.java
rename to core/store/dist/src/main/java/org/onlab/onos/store/device/impl/VersionedValue.java
index 2152eb5..1a85c53 100644
--- a/core/store/src/main/java/org/onlab/onos/store/device/impl/VersionedValue.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/device/impl/VersionedValue.java
@@ -3,7 +3,7 @@
 import org.onlab.onos.store.Timestamp;
 
 /**
- * Wrapper class for a entity that is versioned 
+ * Wrapper class for a entity that is versioned
  * and can either be up or down.
  *
  * @param <T> type of the value.
@@ -12,13 +12,13 @@
     private final T entity;
     private final Timestamp timestamp;
     private final boolean isUp;
-    
+
     public VersionedValue(T entity, boolean isUp, Timestamp timestamp) {
         this.entity = entity;
         this.isUp = isUp;
         this.timestamp = timestamp;
     }
-    
+
     /**
      * Returns the value.
      * @return value.
@@ -26,7 +26,7 @@
     public T entity() {
         return entity;
     }
-    
+
     /**
      * Tells whether the entity is up or down.
      * @return true if up, false otherwise.
@@ -34,7 +34,7 @@
     public boolean isUp() {
         return isUp;
     }
-    
+
     /**
      * Returns the timestamp (version) associated with this entity.
      * @return timestamp.
diff --git a/core/store/dist/src/main/java/org/onlab/onos/store/impl/OnosTimestamp.java b/core/store/dist/src/main/java/org/onlab/onos/store/impl/OnosTimestamp.java
index 5b68d1a..2005582 100644
--- a/core/store/dist/src/main/java/org/onlab/onos/store/impl/OnosTimestamp.java
+++ b/core/store/dist/src/main/java/org/onlab/onos/store/impl/OnosTimestamp.java
@@ -84,4 +84,4 @@
     public int sequenceNumber() {
         return sequenceNumber;
     }
-}
\ No newline at end of file
+}
diff --git a/core/store/hz/src/main/java/org/onlab/onos/store/cluster/impl/DistributedClusterStore.java b/core/store/hz/src/main/java/org/onlab/onos/store/cluster/impl/DistributedClusterStore.java
index 004f807..a76e373 100644
--- a/core/store/hz/src/main/java/org/onlab/onos/store/cluster/impl/DistributedClusterStore.java
+++ b/core/store/hz/src/main/java/org/onlab/onos/store/cluster/impl/DistributedClusterStore.java
@@ -19,7 +19,7 @@
 import org.onlab.onos.cluster.DefaultControllerNode;
 import org.onlab.onos.cluster.NodeId;
 import org.onlab.onos.store.impl.AbsentInvalidatingLoadingCache;
-import org.onlab.onos.store.impl.AbstractDistributedStore;
+import org.onlab.onos.store.impl.AbstractHazelcastStore;
 import org.onlab.onos.store.impl.OptionalCacheLoader;
 import org.onlab.packet.IpPrefix;
 
@@ -38,7 +38,7 @@
 @Component(immediate = true)
 @Service
 public class DistributedClusterStore
-        extends AbstractDistributedStore<ClusterEvent, ClusterStoreDelegate>
+        extends AbstractHazelcastStore<ClusterEvent, ClusterStoreDelegate>
         implements ClusterStore {
 
     private IMap<byte[], byte[]> rawNodes;
diff --git a/core/store/hz/src/main/java/org/onlab/onos/store/cluster/impl/DistributedMastershipStore.java b/core/store/hz/src/main/java/org/onlab/onos/store/cluster/impl/DistributedMastershipStore.java
index 989cc83..0754979 100644
--- a/core/store/hz/src/main/java/org/onlab/onos/store/cluster/impl/DistributedMastershipStore.java
+++ b/core/store/hz/src/main/java/org/onlab/onos/store/cluster/impl/DistributedMastershipStore.java
@@ -22,7 +22,7 @@
 import org.onlab.onos.net.DeviceId;
 import org.onlab.onos.net.MastershipRole;
 import org.onlab.onos.store.impl.AbsentInvalidatingLoadingCache;
-import org.onlab.onos.store.impl.AbstractDistributedStore;
+import org.onlab.onos.store.impl.AbstractHazelcastStore;
 import org.onlab.onos.store.impl.OptionalCacheLoader;
 
 import com.google.common.base.Optional;
@@ -36,7 +36,7 @@
 @Component(immediate = true)
 @Service
 public class DistributedMastershipStore
-extends AbstractDistributedStore<MastershipEvent, MastershipStoreDelegate>
+extends AbstractHazelcastStore<MastershipEvent, MastershipStoreDelegate>
 implements MastershipStore {
 
     private IMap<byte[], byte[]> rawMasters;
diff --git a/core/store/hz/src/main/java/org/onlab/onos/store/common/NoOpClockService.java b/core/store/hz/src/main/java/org/onlab/onos/store/common/NoOpClockService.java
new file mode 100644
index 0000000..ffe5c9f
--- /dev/null
+++ b/core/store/hz/src/main/java/org/onlab/onos/store/common/NoOpClockService.java
@@ -0,0 +1,32 @@
+package org.onlab.onos.store.common;
+
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.onos.cluster.MastershipTerm;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.store.ClockService;
+import org.onlab.onos.store.Timestamp;
+
+// FIXME: Code clone in onos-core-trivial, onos-core-hz
+/**
+ * Dummy implementation of {@link ClockService}.
+ */
+@Component(immediate = true)
+@Service
+public class NoOpClockService implements ClockService {
+
+    @Override
+    public Timestamp getTimestamp(DeviceId deviceId) {
+        return new Timestamp() {
+
+            @Override
+            public int compareTo(Timestamp o) {
+                throw new IllegalStateException("Never expected to be used.");
+            }
+        };
+    }
+
+    @Override
+    public void setMastershipTerm(DeviceId deviceId, MastershipTerm term) {
+    }
+}
diff --git a/core/store/hz/src/main/java/org/onlab/onos/store/device/impl/DistributedDeviceStore.java b/core/store/hz/src/main/java/org/onlab/onos/store/device/impl/DistributedDeviceStore.java
index 3186578..472607a 100644
--- a/core/store/hz/src/main/java/org/onlab/onos/store/device/impl/DistributedDeviceStore.java
+++ b/core/store/hz/src/main/java/org/onlab/onos/store/device/impl/DistributedDeviceStore.java
@@ -27,7 +27,7 @@
 import org.onlab.onos.net.device.PortDescription;
 import org.onlab.onos.net.provider.ProviderId;
 import org.onlab.onos.store.impl.AbsentInvalidatingLoadingCache;
-import org.onlab.onos.store.impl.AbstractDistributedStore;
+import org.onlab.onos.store.impl.AbstractHazelcastStore;
 import org.onlab.onos.store.impl.OptionalCacheLoader;
 import org.slf4j.Logger;
 
@@ -52,7 +52,7 @@
 @Component(immediate = true)
 @Service
 public class DistributedDeviceStore
-        extends AbstractDistributedStore<DeviceEvent, DeviceStoreDelegate>
+        extends AbstractHazelcastStore<DeviceEvent, DeviceStoreDelegate>
         implements DeviceStore {
 
     private final Logger log = getLogger(getClass());
diff --git a/core/store/hz/src/main/java/org/onlab/onos/store/impl/AbstractDistributedStore.java b/core/store/hz/src/main/java/org/onlab/onos/store/impl/AbstractHazelcastStore.java
similarity index 97%
rename from core/store/hz/src/main/java/org/onlab/onos/store/impl/AbstractDistributedStore.java
rename to core/store/hz/src/main/java/org/onlab/onos/store/impl/AbstractHazelcastStore.java
index eb795a8..c4bed4c 100644
--- a/core/store/hz/src/main/java/org/onlab/onos/store/impl/AbstractDistributedStore.java
+++ b/core/store/hz/src/main/java/org/onlab/onos/store/impl/AbstractHazelcastStore.java
@@ -23,7 +23,7 @@
  * Abstraction of a distributed store based on Hazelcast.
  */
 @Component(componentAbstract = true)
-public abstract class AbstractDistributedStore<E extends Event, D extends StoreDelegate<E>>
+public abstract class AbstractHazelcastStore<E extends Event, D extends StoreDelegate<E>>
         extends AbstractStore<E, D> {
 
     protected final Logger log = getLogger(getClass());
diff --git a/core/store/hz/src/main/java/org/onlab/onos/store/link/impl/DistributedLinkStore.java b/core/store/hz/src/main/java/org/onlab/onos/store/link/impl/DistributedLinkStore.java
index 6db9695..38a0179 100644
--- a/core/store/hz/src/main/java/org/onlab/onos/store/link/impl/DistributedLinkStore.java
+++ b/core/store/hz/src/main/java/org/onlab/onos/store/link/impl/DistributedLinkStore.java
@@ -25,7 +25,7 @@
 import org.onlab.onos.net.link.LinkStoreDelegate;
 import org.onlab.onos.net.provider.ProviderId;
 import org.onlab.onos.store.impl.AbsentInvalidatingLoadingCache;
-import org.onlab.onos.store.impl.AbstractDistributedStore;
+import org.onlab.onos.store.impl.AbstractHazelcastStore;
 import org.onlab.onos.store.impl.OptionalCacheLoader;
 import org.slf4j.Logger;
 
@@ -43,7 +43,7 @@
 @Component(immediate = true)
 @Service
 public class DistributedLinkStore
-    extends AbstractDistributedStore<LinkEvent, LinkStoreDelegate>
+    extends AbstractHazelcastStore<LinkEvent, LinkStoreDelegate>
     implements LinkStore {
 
     private final Logger log = getLogger(getClass());
diff --git a/core/store/src/main/java/org/onlab/onos/store/common/ClockService.java b/core/store/src/main/java/org/onlab/onos/store/common/ClockService.java
deleted file mode 100644
index 6df9092..0000000
--- a/core/store/src/main/java/org/onlab/onos/store/common/ClockService.java
+++ /dev/null
@@ -1,25 +0,0 @@
-package org.onlab.onos.store.common;
-
-import org.onlab.onos.cluster.MastershipTerm;
-import org.onlab.onos.net.DeviceId;
-import org.onlab.onos.store.Timestamp;
-
-/**
- * Interface for a logical clock service that vends per device timestamps.
- */
-public interface ClockService {
-    
-    /**
-     * Returns a new timestamp for the specified deviceId.
-     * @param deviceId device identifier.
-     * @return timestamp.
-     */
-    public Timestamp getTimestamp(DeviceId deviceId);
-    
-    /**
-     * Updates the mastership term for the specified deviceId.
-     * @param deviceId device identifier.
-     * @param term mastership term.
-     */
-    public void setMastershipTerm(DeviceId deviceId, MastershipTerm term);
-}
diff --git a/core/store/trivial/src/main/java/org/onlab/onos/net/trivial/impl/NoOpClockService.java b/core/store/trivial/src/main/java/org/onlab/onos/net/trivial/impl/NoOpClockService.java
new file mode 100644
index 0000000..20e410a
--- /dev/null
+++ b/core/store/trivial/src/main/java/org/onlab/onos/net/trivial/impl/NoOpClockService.java
@@ -0,0 +1,32 @@
+package org.onlab.onos.net.trivial.impl;
+
+import org.apache.felix.scr.annotations.Component;
+import org.apache.felix.scr.annotations.Service;
+import org.onlab.onos.cluster.MastershipTerm;
+import org.onlab.onos.net.DeviceId;
+import org.onlab.onos.store.ClockService;
+import org.onlab.onos.store.Timestamp;
+
+//FIXME: Code clone in onos-core-trivial, onos-core-hz
+/**
+ * Dummy implementation of {@link ClockService}.
+ */
+@Component(immediate = true)
+@Service
+public class NoOpClockService implements ClockService {
+
+    @Override
+    public Timestamp getTimestamp(DeviceId deviceId) {
+        return new Timestamp() {
+
+            @Override
+            public int compareTo(Timestamp o) {
+                throw new IllegalStateException("Never expected to be used.");
+            }
+        };
+    }
+
+    @Override
+    public void setMastershipTerm(DeviceId deviceId, MastershipTerm term) {
+    }
+}