NullPointerException (NPE) from FileScanner removeFromRepository?

If you see this NPE in NetBeans 5.0, it means your project source code repository is corrupted. When this happens, the code completion (CTRL-space) for JDK classes (e.g., String, System, etc) stops working. Everything else still works beautifully. But I still found it a little inconvenient, since I seldom type in complete class/method/variable names inside NetBeans. Of course, if you know all the JDK classes, their fields, methods, each method parameters, and you enjoy typing, then it may not be a big problem for you.

Fortunately, there is a simple solution. Several NetBeans developers graciously offered their help: delete this directory $netbeans_user_dir/var/cache/mdrstorage. In a typical installation, it is $HOME/.netbeans/5.0/var/cache/mdrstorage/

For more information, refer to the this issue. If you have an idea, please contribute to this great open-source IDE and make it even better.

PS: I use Google as a debugging tool: everytime I have this type of problem, I google it to see if it happens to others. However, this time Google didn't return any matching results. So I posted it here, hoping Google can do better next time whoever searches for this NPE.

The stacktrace is as follows:

java.lang.NullPointerException at org.netbeans.modules.javacore.scanning.FileScanner.removeFromRepository(FileScanner.java:194) at org.netbeans.modules.javacore.scanning.FileScanner.scan(FileScanner.java:179) [catch] at org.netbeans.modules.javacore.JMManager.scanFiles(JMManager.java:1092) at org.netbeans.modules.javacore.JMManager.resolveCPRoot(JMManager.java:1006) at org.netbeans.modules.javacore.JMManager.resolveCodebases(JMManager.java:815) at org.netbeans.modules.javacore.JMManager$2.run(JMManager.java:769) at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:493) at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:926)

Posted at 10:27PM Mar 17, 2006 by chengfang in NetBeans  |  Comments[3]