org.netbeans.editor.GuardedException: Attempt to insert into guarded block at position 510.
   at org.netbeans.editor.GuardedDocument.preInsertCheck(GuardedDocument.java:238)
   at org.netbeans.editor.BaseDocument.handleInsertString(BaseDocument.java:787)
   at org.netbeans.editor.BaseDocument$FilterBypassImpl.insertString(BaseDocument.java:2408)
   at javax.swing.text.DocumentFilter.insertString(DocumentFilter.java:72)
   at org.openide.text.CloneableEditorSupport$DocFilter.insertString(CloneableEditorSupport.java:3001)
   at org.netbeans.editor.BaseDocument.insertString(BaseDocument.java:763)
   at org.netbeans.api.java.source.ModificationResult.processDocumentLocked(ModificationResult.java:400)
   at org.netbeans.api.java.source.ModificationResult.access$100(ModificationResult.java:95)
   at org.netbeans.api.java.source.ModificationResult$3.run(ModificationResult.java:371)
   at org.netbeans.editor.GuardedDocument.runAtomicAsUser(GuardedDocument.java:347)
   at org.openide.text.NbDocument.runAtomicAsUser(NbDocument.java:463)
Caused: java.io.IOException
   at org.netbeans.api.java.source.ModificationResult.processDocument(ModificationResult.java:391)
   at org.netbeans.api.java.source.ModificationResult.commit2(ModificationResult.java:333)
   at org.netbeans.api.java.source.ModificationResult.access$000(ModificationResult.java:95)
   at org.netbeans.api.java.source.ModificationResult$2.run(ModificationResult.java:241)
   at org.netbeans.editor.GuardedDocument.runAtomic(GuardedDocument.java:317)
   at org.openide.text.NbDocument.runAtomic(NbDocument.java:437)
   at org.netbeans.api.java.source.ModificationResult.commit(ModificationResult.java:238)
   at org.netbeans.api.java.source.ModificationResult.commit(ModificationResult.java:201)
   at org.netbeans.modules.java.hints.introduce.IntroduceHint$IntroduceFieldFix.implement(IntroduceHint.java:1669)
   at org.netbeans.modules.java.hints.introduce.IntroduceAction.doPerformAction(IntroduceAction.java:225)
   at org.netbeans.modules.java.hints.introduce.IntroduceAction.perform(IntroduceAction.java:114)
   at org.netbeans.modules.java.hints.infrastructure.HintAction.doPerform(HintAction.java:115)
   at org.netbeans.modules.java.hints.infrastructure.HintAction.actionPerformed(HintAction.java:88)
   at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
   at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
   at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
   at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
   at javax.swing.AbstractButton.doClick(AbstractButton.java:357)
   at javax.swing.plaf.basic.BasicMenuItemUI.doClick(BasicMenuItemUI.java:809)
   at javax.swing.plaf.basic.BasicMenuItemUI$Handler.mouseReleased(BasicMenuItemUI.java:850)
   at java.awt.Component.processMouseEvent(Component.java:6290)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3267)
   at java.awt.Component.processEvent(Component.java:6055)
   at java.awt.Container.processEvent(Container.java:2039)
   at java.awt.Component.dispatchEventImpl(Component.java:4653)
   at java.awt.Container.dispatchEventImpl(Container.java:2097)
   at java.awt.Component.dispatchEvent(Component.java:4481)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4575)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4236)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4166)
   at java.awt.Container.dispatchEventImpl(Container.java:2083)
   at java.awt.Window.dispatchEventImpl(Window.java:2482)
   at java.awt.Component.dispatchEvent(Component.java:4481)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:648)
   at java.awt.EventQueue.access$000(EventQueue.java:84)
   at java.awt.EventQueue$1.run(EventQueue.java:607)
   at java.awt.EventQueue$1.run(EventQueue.java:605)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
   at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:98)
   at java.awt.EventQueue$2.run(EventQueue.java:621)
   at java.awt.EventQueue$2.run(EventQueue.java:619)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:618)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:158)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)