[ https://issues.apache.org/jira/browse/JCR-1440?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12575280#action_12575280 ] Dominique Pfister commented on JCR-1440: ---------------------------------------- Clustering in jackrabbit requires persistence managers that connect to a shared datasource. I noticed that the persistence managers in your repository.xml use the embedded Derby JDBC driver, which will not work in a clustered setup. Did you try switching to Derby in standalone mode? > NPE Thrown when two Cluster Nodes are hitting the same underlying database. > --------------------------------------------------------------------------- > > Key: JCR-1440 > URL: https://issues.apache.org/jira/browse/JCR-1440 > Project: Jackrabbit > Issue Type: Bug > Affects Versions: 1.4, core 1.4.1 > Environment: Vista JDK 1.5.0_12. Using Derby and Derby Client 10.1.2.1 > Reporter: Micah Whitacre > Priority: Critical > Attachments: SimpleJackRabbitTest.zip > > > I've created a test that creates two repositories with clustering enabled that are backed by the same database. Using the following workflow causes a NullPointerException to be thrown. > The workflow I'm using is: > The root node is versioned. > ClusterNode1 creates a versioned child node named "foo". > The test waits to make sure the syncDelay has passed so ClusterNode2 will notice the newly created node. > ClusterNode2 retrieves the "foo" child node and removes it. > The test waits for the change ClusterNode1 to sync with that change. > ClusterNode1 tries to create another new node however a NullPointerException is thrown when the it tries to checkout the rootNode. > java.lang.NullPointerException: null values not allowed > at org.apache.commons.collections.map.AbstractReferenceMap.put(AbstractReferenceMap.java:251) > at org.apache.jackrabbit.core.version.VersionManagerImpl.getItem(VersionManagerImpl.java:280) > at org.apache.jackrabbit.core.version.XAVersionManager.getItem(XAVersionManager.java:334) > at org.apache.jackrabbit.core.version.AbstractVersionManager.getVersion(AbstractVersionManager.java:87) > at org.apache.jackrabbit.core.NodeImpl.getBaseVersion(NodeImpl.java:3198) > at org.apache.jackrabbit.core.NodeImpl.checkout(NodeImpl.java:2991) > at com.cerner.system.configuration.repository.jcr.SimpleJackrabbitConflictTest.testNullPointerExceptionThrown(SimpleJackrabbitConflictTest.java:96) -- This message is automatically generated by JIRA. - You can reply to this email to add a comment to the issue online.