java.lang.IllegalArgumentException: hostname can't be null
   at java.net.InetSocketAddress.<init>(InetSocketAddress.java:139)
   at org.netbeans.modules.weblogic.common.api.WebLogicRuntime.ping(WebLogicRuntime.java:623)
   at org.netbeans.modules.weblogic.common.api.WebLogicRuntime.ping(WebLogicRuntime.java:612)
   at org.netbeans.modules.weblogic.common.api.WebLogicRuntime.isRunning(WebLogicRuntime.java:500)
   at org.netbeans.modules.j2ee.weblogic9.optional.WLStartServer.isRunning(WLStartServer.java:124)
   at org.netbeans.modules.j2ee.deployment.impl.ServerInstance$3.run(ServerInstance.java:902)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1443)
   at org.netbeans.modules.openide.util.GlobalLookup.execute(GlobalLookup.java:68)
   at org.openide.util.lookup.Lookups.executeWith(Lookups.java:303)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2058)