| Occasional NullPointerException on TableEditor [message #1742913] |
Thu, 08 September 2016 10:33  |
Eclipse User |
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Hi all,
I use TableViewer in my standalone RWT application. The table contains paginated data with TableEditor, however when navigating pages, I occassionally encounter NullPointerException pointing to the TableEditor. Below is the stacktrace:
org.eclipse.swt.SWTException: Failed to execute runnable (java.lang.NullPointerException)
at org.eclipse.swt.SWT.error(SWT.java:3708)
at org.eclipse.swt.SWT.error(SWT.java:3631)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:199)
at org.eclipse.swt.widgets.Display.runPendingMessages(Display.java:1201)
at org.eclipse.swt.widgets.Display.safeReadAndDispatch(Display.java:1181)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:1173)
at org.eclipse.rap.rwt.internal.lifecycle.ProcessAction.execute(ProcessAction.java:29)
at org.eclipse.rap.rwt.internal.lifecycle.PhaseExecutor.execute(PhaseExecutor.java:38)
at org.eclipse.rap.rwt.internal.lifecycle.SimpleLifeCycle.execute(SimpleLifeCycle.java:46)
at org.eclipse.rap.rwt.internal.service.RWTMessageHandler.executeLifeCycle(RWTMessageHandler.java:57)
at org.eclipse.rap.rwt.internal.service.RWTMessageHandler.handleMessage(RWTMessageHandler.java:41)
at org.eclipse.rap.rwt.internal.remote.MessageChainElement.handleMessage(MessageChainElement.java:29)
at org.eclipse.rap.rwt.internal.service.LifeCycleServiceHandler.processMessage(LifeCycleServiceHandler.java:128)
at org.eclipse.rap.rwt.internal.service.LifeCycleServiceHandler.processUIRequest(LifeCycleServiceHandler.java:100)
at org.eclipse.rap.rwt.internal.service.LifeCycleServiceHandler.synchronizedService(LifeCycleServiceHandler.java:75)
at org.eclipse.rap.rwt.internal.service.LifeCycleServiceHandler.service(LifeCycleServiceHandler.java:66)
at org.eclipse.rap.rwt.engine.RWTServlet.handleValidRequest(RWTServlet.java:135)
at org.eclipse.rap.rwt.engine.RWTServlet.handleRequest(RWTServlet.java:117)
at org.eclipse.rap.rwt.engine.RWTServlet.doPost(RWTServlet.java:107)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:286)
at weblogic.servlet.internal.StubSecurityHelper$ServletServiceAction.run(StubSecurityHelper.java:260)
at weblogic.servlet.internal.StubSecurityHelper.invokeServlet(StubSecurityHelper.java:137)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:350)
at weblogic.servlet.internal.ServletStubImpl.execute(ServletStubImpl.java:247)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.wrapRun(WebAppServletContext.java:3679)
at weblogic.servlet.internal.WebAppServletContext$ServletInvocationAction.run(WebAppServletContext.java:3649)
at weblogic.security.acl.internal.AuthenticatedSubject.doAs(AuthenticatedSubject.java:326)
at weblogic.security.service.SecurityManager.runAsForUserCode(SecurityManager.java:197)
at weblogic.servlet.provider.WlsSecurityProvider.runAsForUserCode(WlsSecurityProvider.java:203)
at weblogic.servlet.provider.WlsSubjectHandle.run(WlsSubjectHandle.java:71)
at weblogic.servlet.internal.WebAppServletContext.doSecuredExecute(WebAppServletContext.java:2433)
at weblogic.servlet.internal.WebAppServletContext.securedExecute(WebAppServletContext.java:2281)
at weblogic.servlet.internal.WebAppServletContext.execute(WebAppServletContext.java:2259)
at weblogic.servlet.internal.ServletRequestImpl.runInternal(ServletRequestImpl.java:1686)
at weblogic.servlet.internal.ServletRequestImpl.run(ServletRequestImpl.java:1646)
at weblogic.servlet.provider.ContainerSupportProviderImpl$WlsRequestExecutor.run(ContainerSupportProviderImpl.java:270)
at weblogic.invocation.ComponentInvocationContextManager._runAs(ComponentInvocationContextManager.java:348)
at weblogic.invocation.ComponentInvocationContextManager.runAs(ComponentInvocationContextManager.java:333)
at weblogic.work.LivePartitionUtility.doRunWorkUnderContext(LivePartitionUtility.java:54)
at weblogic.work.PartitionUtility.runWorkUnderContext(PartitionUtility.java:41)
at weblogic.work.SelfTuningWorkManagerImpl.runWorkUnderContext(SelfTuningWorkManagerImpl.java:640)
at weblogic.work.ExecuteThread.execute(ExecuteThread.java:406)
at weblogic.work.ExecuteThread.run(ExecuteThread.java:346)
Caused by: java.lang.NullPointerException
at org.eclipse.swt.custom.TableEditor.computeBounds(TableEditor.java:118)
at org.eclipse.swt.custom.ControlEditor.layout(ControlEditor.java:230)
at org.eclipse.swt.custom.TableEditor.layout(TableEditor.java:268)
at org.eclipse.swt.custom.TableEditor$2.run(TableEditor.java:108)
at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:38)
at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:193)
... 42 more
I use a TableEditor because I want to draw a button in one of the column. Actually I want to draw an Hyperlink but it does not seem to possible, but that's another topic.
Attached is my implementation of ColumnLabelProvider where I use TableEditor.
I use RAP 3.1.0.
Any help would be greatly appreciated.
Thanks & Regards,
Setya
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| Re: Occasional NullPointerException on TableEditor [message #1743436 is a reply to message #1742987] |
Thu, 15 September 2016 08:48  |
| Eclipse User |
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Hi Ivan,
No, I did not modify the source code.
From my observation it seems that we have race condition here. When item is check for null at initial method it's still OK, then along the way dispose was called, and item became null.
I think it's caused by our code:
for (TableEditor tableEditor : TABLE_EDITORS)
{
if (tableEditor.getEditor() != null)
tableEditor.getEditor().dispose();
tableEditor.dispose();
}
After I remove 'tableEditor.dispose', the error is gone.
Is it enough just calling tableEditor.getEditor().dispose() like above ?
Thanks & Regards,
Setya
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