出现错误如下：
提示错误信息：Could not open the editor: An unexpected exception was thrown.
java.lang.NullPointerException
at com.genuitec.eclipse.struts.editor.modeler.model.StrutsConfigDiagram.processAction(StrutsConfigDiagram.java:574)
at com.genuitec.eclipse.struts.editor.modeler.model.StrutsConfigDiagram.synchronizeDiagram(StrutsConfigDiagram.java:479)
at com.genuitec.eclipse.struts.editor.modeler.model.StrutsConfigDiagram.differedSynchronize(StrutsConfigDiagram.java:120)
at com.genuitec.eclipse.struts.editor.multipage.StrutsConfigEditor.createPages(StrutsConfigEditor.java:296)
at org.eclipse.ui.part.MultiPageEditorPart.createPartControl(MultiPageEditorPart.java:357)
at org.eclipse.ui.internal.EditorReference.createPartHelper(EditorReference.java:662)
at org.eclipse.ui.internal.EditorReference.createPart(EditorReference.java:462)
at org.eclipse.ui.internal.WorkbenchPartReference.getPart(WorkbenchPartReference.java:595)
at org.eclipse.ui.internal.PartPane.setVisible(PartPane.java:313)
at org.eclipse.ui.internal.presentations.PresentablePart.setVisible(PresentablePart.java:180)
at org.eclipse.ui.internal.presentations.util.PresentablePartFolder.select(PresentablePartFolder.java:270)
at org.eclipse.ui.internal.presentations.util.LeftToRightTabOrder.select(LeftToRightTabOrder.java:65)
at org.eclipse.ui.internal.presentations.util.TabbedStackPresentation.selectPart(TabbedStackPresentation.java:473)
at org.eclipse.ui.internal.PartStack.refreshPresentationSelection(PartStack.java:1256)
at org.eclipse.ui.internal.PartStack.setSelection(PartStack.java:1209)
at org.eclipse.ui.internal.PartStack.showPart(PartStack.java:1608)
at org.eclipse.ui.internal.PartStack.add(PartStack.java:499)
at org.eclipse.ui.internal.EditorStack.add(EditorStack.java:103)
at org.eclipse.ui.internal.PartStack.add(PartStack.java:485)
at org.eclipse.ui.internal.EditorStack.add(EditorStack.java:112)......
出现这个异常好像是跟打开struts配置文件的插件有关，它每次操作完xml后，好像会生成一个同名的.mex的文件，一般报这个错误就是跟这个文件有关，我们用cvs或者svn提交的时候，就会看到这个文件也会提示提交。
这边就有两种解决方案，第一种，选中要打开的xml，右键--> open with -->myeclipse xml editor；第二种，关闭myeclipse，打开项目的物理目录，找到与xml同名的.mex文件，删除掉，启动MyEclipse，然后双击，或者右键，选择用“MyEclipse Struts Config Editor”打开struts-config.xml文件，会弹出一个窗口，说找不到文件“.struts-config.mex”，问是否创建，点击“OK”按钮。