java.util.ConcurrentModificationException
   at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:901)
   at java.util.ArrayList$Itr.next(ArrayList.java:851)
   at bluej.editor.moe.NaviView.enqueueRepaint(NaviView.java:447)
   at bluej.editor.moe.NaviView.repaintModel(NaviView.java:215)
   at bluej.editor.moe.NVDrawPane.repaint(NVDrawPane.java:108)
   at java.awt.Component.repaint(Component.java:3354)
   at bluej.editor.moe.MoePlainView.damageLineRange(MoePlainView.java:362)
   at bluej.editor.moe.MoePlainView.updateDamage(MoePlainView.java:407)
   at bluej.editor.moe.NaviviewView.updateDamage(NaviviewView.java:180)
   at bluej.editor.moe.MoePlainView.removeUpdate(MoePlainView.java:440)
   at javax.swing.plaf.basic.BasicTextUI$RootView.removeUpdate(BasicTextUI.java:1624)
   at javax.swing.plaf.basic.BasicTextUI$UpdateHandler.removeUpdate(BasicTextUI.java:1884)
   at org.netbeans.lib.editor.util.swing.PriorityDocumentListenerList.removeUpdate(PriorityDocumentListenerList.java:116)
   at javax.swing.text.AbstractDocument.fireRemoveUpdate(AbstractDocument.java:259)
   at org.netbeans.editor.BaseDocument.fireRemoveUpdate(BaseDocument.java:1627)
   at org.netbeans.editor.BaseDocument.handleRemove(BaseDocument.java:1015)
   at org.netbeans.editor.BaseDocument$FilterBypassImpl.remove(BaseDocument.java:2583)
   at javax.swing.text.DocumentFilter.remove(DocumentFilter.java:79)
   at org.openide.text.CloneableEditorSupport$DocFilter.remove(CloneableEditorSupport.java:2389)
   at org.netbeans.editor.BaseDocument.remove(BaseDocument.java:931)
   at org.netbeans.modules.editor.lib2.document.TrailingWhitespaceRemoveProcessor.removeWhitespaceOnLine(TrailingWhitespaceRemoveProcessor.java:92)
   at org.netbeans.modules.editor.lib2.document.TrailingWhitespaceRemoveProcessor.removeWhitespace(TrailingWhitespaceRemoveProcessor.java:202)
   at org.netbeans.modules.editor.lib.TrailingWhitespaceRemove.performTask(TrailingWhitespaceRemove.java:92)
   at org.netbeans.modules.editor.lib.BeforeSaveTasks$TaskRunnable$1.run(BeforeSaveTasks.java:173)
   at org.netbeans.editor.GuardedDocument.runAtomicAsUser(GuardedDocument.java:356)
   at org.netbeans.modules.editor.lib.BeforeSaveTasks$TaskRunnable.run(BeforeSaveTasks.java:156)
   at org.netbeans.gradle.project.java.tasks.CompileOnSaveAction.runLocked(CompileOnSaveAction.java:56)
   at org.netbeans.modules.editor.lib.BeforeSaveTasks$TaskRunnable.run(BeforeSaveTasks.java:153)
   at org.commonquail.linefeed.EofLineFeed.runLocked(EofLineFeed.java:64)
   at org.netbeans.modules.editor.lib.BeforeSaveTasks$TaskRunnable.run(BeforeSaveTasks.java:153)
   at org.netbeans.modules.editor.lib.TrailingWhitespaceRemove.runLocked(TrailingWhitespaceRemove.java:102)
   at org.netbeans.modules.editor.lib.BeforeSaveTasks$TaskRunnable.run(BeforeSaveTasks.java:153)
   at org.netbeans.modules.editor.impl.ReformatBeforeSaveTask.runLocked(ReformatBeforeSaveTask.java:124)
   at org.netbeans.modules.editor.lib.BeforeSaveTasks$TaskRunnable.run(BeforeSaveTasks.java:153)
   at org.netbeans.modules.editor.lib.BeforeSaveTasks.runTasks(BeforeSaveTasks.java:130)
   at org.netbeans.modules.editor.lib.BeforeSaveTasks$2.run(BeforeSaveTasks.java:111)
   at org.openide.text.CloneableEditorSupport.saveDocumentImpl(CloneableEditorSupport.java:753)
   at org.openide.text.CloneableEditorSupport.saveDocument(CloneableEditorSupport.java:644)
   at org.openide.text.DataEditorSupport.superSaveDoc(DataEditorSupport.java:607)
   at org.openide.text.DataEditorSupport$SaveImpl.run(DataEditorSupport.java:1378)
   at org.openide.filesystems.EventControl.runAtomicAction(EventControl.java:127)
   at org.openide.filesystems.FileSystem.runAtomicAction(FileSystem.java:519)
   at org.openide.filesystems.FileUtil.runAtomicAction(FileUtil.java:423)
   at org.openide.text.DataEditorSupport.saveDocument(DataEditorSupport.java:603)
   at org.netbeans.modules.openide.loaders.SimpleES$SaveCookieImpl.save(SimpleES.java:226)
   at org.netbeans.core.NbLifecycleManager.saveAll(NbLifecycleManager.java:97)
   at org.remikz.netbeans.AutoSaveModified.AutoSaveModified.run(AutoSaveModified.java:33)
   at org.openide.util.RequestProcessor$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)