diff --git oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/segment/SegmentNodeStoreService.java oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/segment/SegmentNodeStoreService.java
index 5574a0a..77abf78 100644
--- oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/segment/SegmentNodeStoreService.java
+++ oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/segment/SegmentNodeStoreService.java
@@ -16,6 +16,7 @@
  */
 package org.apache.jackrabbit.oak.plugins.segment;
 
+import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.base.Preconditions.checkState;
 import static java.util.Collections.emptyMap;
 import static org.apache.jackrabbit.oak.commons.PropertiesUtil.toBoolean;
@@ -87,6 +88,9 @@ import org.osgi.service.component.ComponentContext;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.util.concurrent.locks.ReadWriteLock;
+import java.util.concurrent.locks.ReentrantReadWriteLock;
+
 /**
  * An OSGi wrapper for the segment node store.
  */
@@ -263,44 +267,97 @@ public class SegmentNodeStoreService extends ProxyNodeStore
     )
     public static final String PROP_BLOB_GC_MAX_AGE = "blobGcMaxAgeInSecs";
 
+    private final ReadWriteLock lock = new ReentrantReadWriteLock();
+
     @Override
-    protected synchronized SegmentNodeStore getNodeStore() {
-        checkState(delegate != null, "service must be activated when used");
-        return delegate;
+    protected SegmentNodeStore getNodeStore() {
+        lock.readLock().lock();
+
+        try {
+            return checkNotNull(delegate, "service must be activated when used");
+        } finally {
+            lock.readLock().unlock();
+        }
+
     }
 
     @Activate
     private void activate(ComponentContext context) throws IOException {
+        lock.writeLock().lock();
+
+        try {
+            safeActivate(context);
+        } finally {
+            lock.writeLock().unlock();
+        }
+    }
+
+    @Deactivate
+    private void deactivate() {
+        lock.writeLock().lock();
+
+        try {
+            safeDeactivate();
+        } finally {
+            lock.writeLock().unlock();
+        }
+    }
+
+    protected void bindBlobStore(BlobStore blobStore) throws IOException {
+        lock.writeLock().lock();
+
+        try {
+            safeBindBlobStore(blobStore);
+        } finally {
+            lock.writeLock().unlock();
+        }
+    }
+
+    protected void unbindBlobStore(BlobStore blobStore) {
+        lock.writeLock().lock();
+
+        try {
+            safeUnbindBlobStore(blobStore);
+        } finally {
+            lock.writeLock().unlock();
+        }
+    }
+
+    private void safeActivate(ComponentContext context) throws IOException {
         this.context = context;
         this.customBlobStore = Boolean.parseBoolean(lookup(context, CUSTOM_BLOB_STORE));
 
-        if (blobStore == null && customBlobStore) {
-            log.info("BlobStore use enabled. SegmentNodeStore would be initialized when BlobStore would be available");
-        } else {
-            registerNodeStore();
-        }
+        registerNodeStore();
     }
 
-    public void registerNodeStore() throws IOException {
-        if (registerSegmentStore()) {
-            boolean standby = toBoolean(lookup(context, STANDBY), false);
-            providerRegistration = context.getBundleContext().registerService(
-                    SegmentStoreProvider.class.getName(), this, null);
-            if (!standby) {
-                Dictionary<String, Object> props = new Hashtable<String, Object>();
-                props.put(Constants.SERVICE_PID, SegmentNodeStore.class.getName());
-                props.put("oak.nodestore.description", new String[]{"nodeStoreType=segment"});
-                storeRegistration = context.getBundleContext().registerService(
-                        NodeStore.class.getName(), this, props);
-            }
+    private void safeDeactivate() {
+        unregisterNodeStore();
+    }
+
+    private void safeBindBlobStore(BlobStore blobStore) throws IOException {
+        unregisterNodeStore();
+        this.blobStore = blobStore;
+        registerNodeStore();
+    }
+
+    private void safeUnbindBlobStore(BlobStore blobStore) {
+        if (this.blobStore == blobStore) {
+            unregisterNodeStore();
+            this.blobStore = null;
         }
     }
 
-    public synchronized boolean registerSegmentStore() throws IOException {
+    private void registerNodeStore() throws IOException {
         if (context == null) {
             log.info("Component still not activated. Ignoring the initialization call");
-            return false;
+            return;
         }
+
+        if (blobStore == null && customBlobStore) {
+            log.info("BlobStore use enabled. SegmentNodeStore would be initialized when BlobStore would be available");
+            return;
+        }
+
         Dictionary<?, ?> properties = context.getProperties();
         name = String.valueOf(properties.get(NAME));
 
@@ -440,79 +497,86 @@ public class SegmentNodeStoreService extends ProxyNodeStore
                 "Segment node store compaction strategy settings");
 
         log.info("SegmentNodeStore initialized");
-        return true;
-    }
 
-    private static String lookup(ComponentContext context, String property) {
-        if (context.getProperties().get(property) != null) {
-            return context.getProperties().get(property).toString();
-        }
-        if (context.getBundleContext().getProperty(property) != null) {
-            return context.getBundleContext().getProperty(property);
+        boolean standby = toBoolean(lookup(context, STANDBY), false);
+        providerRegistration = context.getBundleContext().registerService(
+                SegmentStoreProvider.class.getName(), this, null);
+        if (!standby) {
+            Dictionary<String, Object> props = new Hashtable<String, Object>();
+            props.put(Constants.SERVICE_PID, SegmentNodeStore.class.getName());
+            props.put("oak.nodestore.description", new String[]{"nodeStoreType=segment"});
+            storeRegistration = context.getBundleContext().registerService(
+                    NodeStore.class.getName(), this, props);
         }
-        return null;
     }
 
-    @Deactivate
-    public synchronized void deactivate() {
-        unregisterNodeStore();
-
-        if (observerTracker != null) {
-            observerTracker.stop();
-        }
-        if (gcMonitor != null) {
-            gcMonitor.stop();
-        }
-        delegate = null;
-        if (store != null) {
-            store.close();
-            store = null;
+    private void unregisterNodeStore() {
+        if (storeRegistration != null) {
+            storeRegistration.unregister();
+            storeRegistration = null;
         }
-    }
 
-    protected void bindBlobStore(BlobStore blobStore) throws IOException {
-        this.blobStore = blobStore;
-        registerNodeStore();
-    }
-
-    protected void unbindBlobStore(BlobStore blobStore){
-        this.blobStore = null;
-        unregisterNodeStore();
-    }
-
-    private void unregisterNodeStore() {
-        if(providerRegistration != null){
+        if (providerRegistration != null) {
             providerRegistration.unregister();
             providerRegistration = null;
         }
-        if(storeRegistration != null){
-            storeRegistration.unregister();
-            storeRegistration = null;
+
+        if (compactionStrategyRegistration != null) {
+            compactionStrategyRegistration.unregister();
+            compactionStrategyRegistration = null;
         }
-        if (checkpointRegistration != null) {
-            checkpointRegistration.unregister();
-            checkpointRegistration = null;
+
+        if (blobGCRegistration != null) {
+            blobGCRegistration.unregister();
+            blobGCRegistration = null;
         }
+
         if (revisionGCRegistration != null) {
             revisionGCRegistration.unregister();
             revisionGCRegistration = null;
         }
-        if (blobGCRegistration != null) {
-            blobGCRegistration.unregister();
-            blobGCRegistration = null;
+
+        if (checkpointRegistration != null) {
+            checkpointRegistration.unregister();
+            checkpointRegistration = null;
         }
-        if (compactionStrategyRegistration != null) {
-            compactionStrategyRegistration.unregister();
-            compactionStrategyRegistration = null;
+
+        if (executor != null) {
+            executor.stop();
+            executor = null;
         }
+
+        if (observerTracker != null) {
+            observerTracker.stop();
+            observerTracker = null;
+        }
+
         if (fsgcMonitorMBean != null) {
             fsgcMonitorMBean.unregister();
             fsgcMonitorMBean = null;
         }
-        if (executor != null) {
-            executor.stop();
-            executor = null;
+
+        delegate = null;
+
+        if (store != null) {
+            store.close();
+            store = null;
         }
+
+        if (gcMonitor != null) {
+            gcMonitor.stop();
+            gcMonitor = null;
+        }
+    }
+
+    private static String lookup(ComponentContext context, String property) {
+        if (context.getProperties().get(property) != null) {
+            return context.getProperties().get(property).toString();
+        }
+        if (context.getBundleContext().getProperty(property) != null) {
+            return context.getBundleContext().getProperty(property);
+        }
+        return null;
     }
 
     /**
@@ -521,7 +585,13 @@ public class SegmentNodeStoreService extends ProxyNodeStore
      */
     @Override
     public SegmentStore getSegmentStore() {
-        return store;
+        lock.readLock().lock();
+
+        try {
+            return checkNotNull(store, "Segment store not activated");
+        } finally {
+            lock.readLock().unlock();
+        }
     }
 
     //------------------------------------------------------------< Observable >---