java.lang.NullPointerException
   at org.netbeans.modules.maven.j2ee.web.WebRunCustomizerPanel$7.run(WebRunCustomizerPanel.java:543)
   at org.openide.util.Mutex.leaveImpl(Mutex.java:906)
   at org.openide.util.Mutex.leave(Mutex.java:839)
   at org.openide.util.Mutex.writeAccess(Mutex.java:399)
   at org.netbeans.modules.project.uiapi.CustomizerDialog$OptionListener$2.run(CustomizerDialog.java:294)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1411)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1991)