diff --git a/oak-core-spi/src/main/java/org/apache/jackrabbit/oak/spi/namespace/NamespaceConstants.java b/oak-core-spi/src/main/java/org/apache/jackrabbit/oak/spi/namespace/NamespaceConstants.java
index 668fa28518..ccbf8bde15 100644
--- a/oak-core-spi/src/main/java/org/apache/jackrabbit/oak/spi/namespace/NamespaceConstants.java
+++ b/oak-core-spi/src/main/java/org/apache/jackrabbit/oak/spi/namespace/NamespaceConstants.java
@@ -43,6 +43,10 @@ public interface NamespaceConstants {
     String PREFIX_XMLNS = "xmlns";
     String NAMESPACE_XMLNS = "http://www.w3.org/2000/xmlns/";
 
+    // additional Oak namespace
+    String PREFIX_OAK = "oak";
+    String NAMESPACE_OAK = "http://jackrabbit.apache.org/oak/ns/1.0";
+
     /**
      * Reserved namespace prefixes as defined in jackrabbit 2
      */
@@ -53,7 +57,8 @@ public interface NamespaceConstants {
             NamespaceRegistry.PREFIX_MIX,
             PREFIX_XMLNS,
             PREFIX_REP,
-            PREFIX_SV
+            PREFIX_SV,
+            PREFIX_OAK
     ));
 
     /**
@@ -66,7 +71,8 @@ public interface NamespaceConstants {
             NamespaceRegistry.NAMESPACE_MIX,
             NAMESPACE_XMLNS,
             NAMESPACE_REP,
-            NAMESPACE_SV
+            NAMESPACE_SV,
+            NAMESPACE_OAK
     ));
 
     // index nodes for faster lookup
diff --git a/oak-core-spi/src/main/java/org/apache/jackrabbit/oak/spi/namespace/package-info.java b/oak-core-spi/src/main/java/org/apache/jackrabbit/oak/spi/namespace/package-info.java
index 5b7f7acb78..89f79491d7 100644
--- a/oak-core-spi/src/main/java/org/apache/jackrabbit/oak/spi/namespace/package-info.java
+++ b/oak-core-spi/src/main/java/org/apache/jackrabbit/oak/spi/namespace/package-info.java
@@ -14,7 +14,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-@Version("1.0.0")
+@Version("1.1.0")
 package org.apache.jackrabbit.oak.spi.namespace;
 
 import org.osgi.annotation.versioning.Version;
\ No newline at end of file
diff --git a/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/name/NamespaceEditor.java b/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/name/NamespaceEditor.java
index 2a036b99b0..886c303549 100644
--- a/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/name/NamespaceEditor.java
+++ b/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/name/NamespaceEditor.java
@@ -26,15 +26,15 @@ import static org.apache.jackrabbit.oak.spi.namespace.NamespaceConstants.REP_NAM
 import static org.apache.jackrabbit.oak.spi.namespace.NamespaceConstants.REP_NSDATA;
 import static org.apache.jackrabbit.oak.spi.namespace.NamespaceConstants.REP_URIS;
 import static org.apache.jackrabbit.oak.plugins.name.Namespaces.isValidPrefix;
-import static org.apache.jackrabbit.oak.plugins.name.Namespaces.safeGet;
 
 import java.util.Locale;
 import java.util.Set;
 
 import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Iterables;
+
 import org.apache.jackrabbit.oak.api.CommitFailedException;
 import org.apache.jackrabbit.oak.api.PropertyState;
-import org.apache.jackrabbit.oak.plugins.tree.factories.TreeFactory;
 import org.apache.jackrabbit.oak.spi.commit.DefaultEditor;
 import org.apache.jackrabbit.oak.spi.commit.Editor;
 import org.apache.jackrabbit.oak.spi.namespace.NamespaceConstants;
@@ -89,8 +89,7 @@ class NamespaceEditor extends DefaultEditor {
     }
 
     private static boolean containsValue(NodeState namespaces, String value) {
-        return safeGet(TreeFactory.createReadOnlyTree(namespaces.getChildNode(REP_NSDATA)),
-                REP_URIS).contains(value);
+        return Iterables.contains(namespaces.getChildNode(REP_NSDATA).getStrings(REP_URIS), value);
     }
 
     @Override
@@ -130,7 +129,7 @@ class NamespaceEditor extends DefaultEditor {
         if (!modified) {
             return;
         }
-        Namespaces.buildIndexNode(builder.child(JCR_SYSTEM).child(
+        Namespaces.buildIndexNode(builder.getChildNode(JCR_SYSTEM).child(
                 REP_NAMESPACES));
     }
 
diff --git a/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/name/Namespaces.java b/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/name/Namespaces.java
index 5f6f557342..46185c5beb 100644
--- a/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/name/Namespaces.java
+++ b/oak-core/src/main/java/org/apache/jackrabbit/oak/plugins/name/Namespaces.java
@@ -107,6 +107,9 @@ public class Namespaces implements NamespaceConstants {
         namespaces.setProperty(PREFIX_SV, NAMESPACE_SV);
         namespaces.setProperty(PREFIX_REP, NAMESPACE_REP);
 
+        // Oak Namespace
+        namespaces.setProperty(PREFIX_OAK, NAMESPACE_OAK);
+
         return namespaces;
     }