Netbeans plugin ClassNotFoundException for existing class

I am working on a Netbeans plugin based on the http://platform.netbeans.org/tutorials/nbm-code-completion.html tutorial. When I run and debug my plugin, an exception is thrown:

java.lang.ClassNotFoundException: javax.swing.text.BadLocationException on org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal (BundleLoader.java:513) in org.eclipse.osgi.internal.loader.BundleLoader (BundleLaderClass .java: 429) in org.eclipse.osgi.internal.loader.BundleLoader.findClass (BundleLoader.java:417) in org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass (DefaultClassLoader.java:107) in java. lang.ClassLoader.loadClass (ClassLoader.java:356) Thrown by: java.lang.NoClassDefFoundError: javax / swing / text / BadLocationException at pl.artpal.hinttest.CodeCompletionProvider $ 1.query (CodeCompletionProvider.java:35) at. spi.editor.completion.support.AsyncCompletionTask.run (AsyncCompletionTask.java:223) at org.openide.util.RequestProcessor $ Task.run (RequestProcessor.java:1452) [catch] at org.openide.util.RequestProcessor $ Processor.run (RequestProcessor.java:2032)

BadLocationException class is part of javax.swing.text package, it must be loaded from rt.jar

Of course my java file has

import javax.swing.text.BadLocationException;

      

        
        
        
      

    

According to netbeans command line debug

javax.swing.text.BadLocationException.class 

      

        
        
        
      

    

doesn't exist, but when I try:

Class.forName("javax.swing.text.BadLocationException").getConstructors()[0].newInstance(new Object[] { "a", 1}).toString()

      

        
        
        
      

    

It works. What's happening?

Netbeans v7.2.1, JDK 1.7.0_13, JRE7, Win7x64, I also have Eclipse on my computer.