1. Create new java application
2. Select window Files and browse to folder "src"
of the application
3. Rename it
--> a NPE is thrown

It is caused by error in method folderRenamed() of
org.netbeans.modules.javacore.RepositoryUpdater

The method should be changed as follows:

    private void folderRenamed(FileRenameEvent fe) {
        FileObject newFo = fe.getFile();
        boolean failed = true;
        
       
JMManager.getDefaultRepository().beginTrans(true);
        try {
            Enumeration children =
newFo.getChildren(true);
            FileObject cpRoot = getCPRoot(newFo);
            if (cpRoot == null) {
                // ignore folders that are not
visible from our merged classpath
                return;
            }
            String dirName =
JMManager.getResourceName(cpRoot, newFo);
            while (children.hasMoreElements()) {
                FileObject f = (FileObject)
children.nextElement();
                if ("java".equals(f.getExt()) &&
!f.isVirtual()) { // NOI18N
                    String oldName =
JMManager.getResourceName(cpRoot, f);
                    String newName =
replaceStart(oldName, dirName, fe.getName());
                    newName = replaceEnd(dirName,
fe.getName());
                    newName =
replaceStart(oldName, dirName, newName);
                    if (DEBUG)
                        System.out.println("Folder
renamed: Resource " + newName + " renamed to " +
oldName); // NOI18N
                    manager.getResource(cpRoot,
oldName).setName(newName);
                }
            }
            failed = false;
        } finally {
           
JMManager.getDefaultRepository().endTrans(failed);
        }
    }