code completion exception

java.lang.IllegalArgumentException
	at org.eclipse.jdt.internal.codeassist.InternalCompletionProposal.<init>(InternalCompletionProposal.java:443)
	at org.codehaus.groovy.eclipse.codeassist.processors.GroovyCompletionProposal.<init>(GroovyCompletionProposal.java:65)
	at org.codehaus.groovy.eclipse.codeassist.processors.GroovyProposalTypeSearchRequestor.createProposal(GroovyProposalTypeSearchRequestor.java:935)
	at org.codehaus.groovy.eclipse.codeassist.processors.GroovyProposalTypeSearchRequestor.proposeConstructor(GroovyProposalTypeSearchRequestor.java:773)
	at org.codehaus.groovy.eclipse.codeassist.processors.GroovyProposalTypeSearchRequestor.processAcceptedConstructors(GroovyProposalTypeSearchRequestor.java:701)
	at org.codehaus.groovy.eclipse.codeassist.processors.ConstructorCompletionProcessor.generateProposals(ConstructorCompletionProcessor.java:64)
	at org.codehaus.groovy.eclipse.codeassist.requestor.GroovyCompletionProposalComputer.internalComputeCompletionProposals(GroovyCompletionProposalComputer.java:156)
	at org.codehaus.groovy.eclipse.codeassist.requestor.GroovyCompletionProposalComputer.computeCompletionProposals(GroovyCompletionProposalComputer.java:108)
	at org.eclipse.jdt.internal.ui.text.java.CompletionProposalComputerDescriptor.computeCompletionProposals(CompletionProposalComputerDescriptor.java:318)
	at org.eclipse.jdt.internal.ui.text.java.CompletionProposalCategory.computeCompletionProposals(CompletionProposalCategory.java:267)
	at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.collectProposals(ContentAssistProcessor.java:283)
	at org.eclipse.jdt.internal.ui.text.java.ContentAssistProcessor.computeCompletionProposals(ContentAssistProcessor.java:243)
	at org.eclipse.jface.text.contentassist.ContentAssistant.computeCompletionProposals(ContentAssistant.java:1830)
	at org.eclipse.jface.text.contentassist.CompletionProposalPopup.computeProposals(CompletionProposalPopup.java:556)
	at org.eclipse.jface.text.contentassist.CompletionProposalPopup.access$16(CompletionProposalPopup.java:553)
	at org.eclipse.jface.text.contentassist.CompletionProposalPopup$2.run(CompletionProposalPopup.java:488)
	at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
	at org.eclipse.jface.text.contentassist.CompletionProposalPopup.showProposals(CompletionProposalPopup.java:482)
	at org.eclipse.jface.text.contentassist.ContentAssistant.showPossibleCompletions(ContentAssistant.java:1656)
	at org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitEditor$AdaptedSourceViewer.doOperation(CompilationUnitEditor.java:183)
	at org.eclipse.ui.texteditor.ContentAssistAction$1.run(ContentAssistAction.java:82)
	at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70)
	at org.eclipse.ui.texteditor.ContentAssistAction.run(ContentAssistAction.java:80)
	at org.eclipse.jface.action.Action.runWithEvent(Action.java:498)
	at org.eclipse.ui.commands.ActionHandler.execute(ActionHandler.java:185)
	at org.eclipse.ui.internal.handlers.LegacyHandlerWrapper.execute(LegacyHandlerWrapper.java:109)
	at org.eclipse.core.commands.Command.executeWithChecks(Command.java:476)
	at org.eclipse.core.commands.ParameterizedCommand.executeWithChecks(ParameterizedCommand.java:508)
	at org.eclipse.ui.internal.handlers.HandlerService.executeCommand(HandlerService.java:169)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.executeCommand(WorkbenchKeyboard.java:468)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.press(WorkbenchKeyboard.java:786)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.processKeyEvent(WorkbenchKeyboard.java:885)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.filterKeySequenceBindings(WorkbenchKeyboard.java:567)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard.access$3(WorkbenchKeyboard.java:508)
	at org.eclipse.ui.internal.keys.WorkbenchKeyboard$KeyDownFilter.handleEvent(WorkbenchKeyboard.java:123)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
	at org.eclipse.swt.widgets.Display.filterEvent(Display.java:1069)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4127)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1457)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1480)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1465)
	at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1494)
	at org.eclipse.swt.widgets.Widget.sendKeyEvent(Widget.java:1490)
	at org.eclipse.swt.widgets.Canvas.sendKeyEvent(Canvas.java:463)
	at org.eclipse.swt.widgets.Control.doCommandBySelector(Control.java:1051)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:5563)
	at org.eclipse.swt.internal.cocoa.OS.objc_msgSend(Native Method)
	at org.eclipse.swt.internal.cocoa.NSResponder.interpretKeyEvents(NSResponder.java:68)
	at org.eclipse.swt.widgets.Composite.keyDown(Composite.java:587)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:5473)
	at org.eclipse.swt.internal.cocoa.OS.objc_msgSendSuper(Native Method)
	at org.eclipse.swt.widgets.Widget.callSuper(Widget.java:220)
	at org.eclipse.swt.widgets.Widget.windowSendEvent(Widget.java:2092)
	at org.eclipse.swt.widgets.Shell.windowSendEvent(Shell.java:2252)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:5535)
	at org.eclipse.swt.internal.cocoa.OS.objc_msgSendSuper(Native Method)
	at org.eclipse.swt.widgets.Display.applicationSendEvent(Display.java:4989)
	at org.eclipse.swt.widgets.Display.applicationProc(Display.java:5138)
	at org.eclipse.swt.internal.cocoa.OS.objc_msgSend(Native Method)
	at org.eclipse.swt.internal.cocoa.NSApplication.sendEvent(NSApplication.java:128)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3610)
	at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2696)
	at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2660)
	at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2494)
	at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:674)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:667)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
	at java.lang.reflect.Method.invoke(Method.java:597)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1410)