title: Installing AJDT I got a Plug-in org.eclipse.jdt.ui was unable to load class org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitEditor
body: <p>After I install the AJDT 2.2.3 on Rational Software Archtect, every Editor displays the error: Plug-in org.eclipse.jdt.ui was unable to load class org.eclipse.jdt.internal.ui.javaeditor.CompilationUnitEditor
  I am using the Rational Software Architect 9 with Eclipse 4.2.2. Used the link (<a href="http://download.eclipse.org/tools/ajdt/42/update">http://download.eclipse.org/tools/ajdt/42/update</a>) to install the AJDT.
  Searching on the web I found this:<a href="http://www.eclipse.org/forums/index.php/t/74968/">http://www.eclipse.org/forums/index.php/t/74968/</a>), but removing the Data Tools did not work for me. 
  I also updated the Data Tools to 1.10.2, and yet not working.</p>
  
  <p>Can anybody help me? </p>
  
  <p>Adding more info:
  I was searching for the installed JRE in preferences, but when I click Preferences -> Java I got an error: "An error has occurred when creating this preference page." And when I try the "Installed JRE's I got a popup: "Unable to create the selected preference page. An error occurred while automatically activating bundle org.eclipse.jdt.debug.ui(1537)"
  Another thing I am not sure if it is clear. The Editors I was mentioning were the Java File Editor, The Package Explorer, the Java View. I tryed to open an .xml file and it seems to work fine.</p>
  
  <p>Here is a picture of the Eclipse error tab: dl.dropboxusercontent.com/u/71227599/ajdt.PNG</p>
  
  <p>Here is the details stack :</p>
  
  <pre><code>org.eclipse.core.runtime.CoreException: Plug-in org.eclipse.jdt.ui was unable to load class org.eclipse.jdt.internal.ui.packageview.PackageExplorerPart.
  at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.throwException(RegistryStrategyOSGI.java:194)
  at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:176)
  at org.eclipse.core.internal.registry.ExtensionRegistry.createExecutableExtension(ExtensionRegistry.java:905)
  at org.eclipse.core.internal.registry.ConfigurationElement.createExecutableExtension(ConfigurationElement.java:243)
  at org.eclipse.core.internal.registry.ConfigurationElementHandle.createExecutableExtension(ConfigurationElementHandle.java:55)
  at org.eclipse.ui.internal.registry.ViewDescriptor.createView(ViewDescriptor.java:62)
  at org.eclipse.ui.internal.ViewReference.createPart(ViewReference.java:112)
  at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.createPart(CompatibilityPart.java:262)
  at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.create(CompatibilityPart.java:299)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:88)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:55)
  at java.lang.reflect.Method.invoke(Method.java:613)
  at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:56)
  at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:861)
  at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:841)
  at org.eclipse.e4.core.internal.di.InjectorImpl.inject(InjectorImpl.java:113)
  at org.eclipse.e4.core.internal.di.InjectorImpl.internalMake(InjectorImpl.java:321)
  at org.eclipse.e4.core.internal.di.InjectorImpl.make(InjectorImpl.java:242)
  at org.eclipse.e4.core.contexts.ContextInjectionFactory.make(ContextInjectionFactory.java:161)
  at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.createFromBundle(ReflectionContributionFactory.java:102)
  at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.doCreate(ReflectionContributionFactory.java:71)
  at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.create(ReflectionContributionFactory.java:53)
  at org.eclipse.e4.ui.workbench.renderers.swt.ContributedPartRenderer.createWidget(ContributedPartRenderer.java:141)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createWidget(PartRenderingEngine.java:894)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:629)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$6.run(PartRenderingEngine.java:520)
  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:505)
  at org.eclipse.e4.ui.workbench.renderers.swt.ElementReferenceRenderer.createWidget(ElementReferenceRenderer.java:74)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createWidget(PartRenderingEngine.java:894)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:629)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:731)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$2(PartRenderingEngine.java:702)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$7.run(PartRenderingEngine.java:696)
  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:681)
  at org.eclipse.e4.ui.workbench.renderers.swt.StackRenderer.showTab(StackRenderer.java:1128)
  at org.eclipse.e4.ui.workbench.renderers.swt.LazyStackRenderer.postProcess(LazyStackRenderer.java:98)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:645)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:731)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$2(PartRenderingEngine.java:702)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$7.run(PartRenderingEngine.java:696)
  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:681)
  at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:59)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:641)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:731)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$2(PartRenderingEngine.java:702)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$7.run(PartRenderingEngine.java:696)
  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:681)
  at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:59)
  at org.eclipse.e4.ui.workbench.renderers.swt.PerspectiveRenderer.processContents(PerspectiveRenderer.java:59)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:641)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:731)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$2(PartRenderingEngine.java:702)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$7.run(PartRenderingEngine.java:696)
  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:681)
  at org.eclipse.e4.ui.workbench.renderers.swt.PerspectiveStackRenderer.showTab(PerspectiveStackRenderer.java:103)
  at org.eclipse.e4.ui.workbench.renderers.swt.LazyStackRenderer.postProcess(LazyStackRenderer.java:98)
  at org.eclipse.e4.ui.workbench.renderers.swt.PerspectiveStackRenderer.postProcess(PerspectiveStackRenderer.java:77)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:645)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:731)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$2(PartRenderingEngine.java:702)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$7.run(PartRenderingEngine.java:696)
  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:681)
  at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:59)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:641)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:731)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$2(PartRenderingEngine.java:702)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$7.run(PartRenderingEngine.java:696)
  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:681)
  at org.eclipse.e4.ui.workbench.renderers.swt.SWTPartRenderer.processContents(SWTPartRenderer.java:59)
  at org.eclipse.e4.ui.workbench.renderers.swt.WBWRenderer.processContents(WBWRenderer.java:647)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:641)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:731)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$2(PartRenderingEngine.java:702)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$7.run(PartRenderingEngine.java:696)
  at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:681)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:987)
  at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
  at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:942)
  at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:86)
  at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:588)
  at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
  at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:543)
  at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
  at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:124)
  at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
  at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
  at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
  at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:353)
  at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180)
  at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
  at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:88)
  at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:55)
  at java.lang.reflect.Method.invoke(Method.java:613)
  at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629)
  at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584)
  at org.eclipse.equinox.launcher.Main.run(Main.java:1438)
  at org.eclipse.equinox.launcher.Main.main(Main.java:1414)
  Caused by: org.eclipse.core.runtime.internal.adaptor.EclipseLazyStarter$TerminatingClassNotFoundException: An error occurred while automatically activating bundle org.eclipse.jdt.ui (1544).
  at org.eclipse.core.runtime.internal.adaptor.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:122)
  at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:469)
  at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:216)
  at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:395)
  at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:464)
  at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:421)
  at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:412)
  at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:690)
  at org.eclipse.osgi.internal.loader.BundleLoader.loadClass(BundleLoader.java:340)
  at org.eclipse.osgi.framework.internal.core.BundleHost.loadClass(BundleHost.java:229)
  at org.eclipse.osgi.framework.internal.core.AbstractBundle.loadClass(AbstractBundle.java:1212)
  at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:174)
  ... 104 more
  Caused by: org.osgi.framework.BundleException: The activator org.eclipse.jdt.internal.ui.JavaPlugin for bundle org.eclipse.jdt.ui is invalid
  at org.eclipse.osgi.framework.internal.core.AbstractBundle.loadBundleActivator(AbstractBundle.java:172)
  at org.eclipse.osgi.framework.internal.core.BundleContextImpl.start(BundleContextImpl.java:679)
  at org.eclipse.osgi.framework.internal.core.BundleHost.startWorker(BundleHost.java:381)
  at org.eclipse.osgi.framework.internal.core.AbstractBundle.start(AbstractBundle.java:300)
  at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:440)
  at org.eclipse.osgi.internal.loader.BundleLoader.setLazyTrigger(BundleLoader.java:263)
  at org.eclipse.core.runtime.internal.adaptor.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107)
  ... 116 more
  Caused by: org.aspectj.apache.bcel.classfile.ClassFormatException: org.eclipse.jdt.core.WorkingCopyOwner is not a Java .class file
  at org.aspectj.apache.bcel.classfile.ClassParser.readID(ClassParser.java:215)
  at org.aspectj.apache.bcel.classfile.ClassParser.parse(ClassParser.java:124)
  at org.aspectj.weaver.bcel.Utility.makeJavaClass(Utility.java:467)
  at org.aspectj.weaver.bcel.BcelWorld.addSourceObjectType(BcelWorld.java:499)
  at org.aspectj.weaver.tools.WeavingAdaptor.ensureDelegateInitialized(WeavingAdaptor.java:513)
  at org.aspectj.weaver.tools.WeavingAdaptor$WeavingClassFileProvider.&lt;init&gt;(WeavingAdaptor.java:843)
  at org.aspectj.weaver.tools.WeavingAdaptor.getWovenBytes(WeavingAdaptor.java:526)
  at org.aspectj.weaver.tools.WeavingAdaptor.weaveClass(WeavingAdaptor.java:363)
  at org.eclipse.equinox.weaving.aspectj.loadtime.OSGiWeavingAdaptor.weaveClass(Unknown Source)
  at org.eclipse.equinox.weaving.aspectj.AspectJWeavingService.preProcess(Unknown Source)
  at org.eclipse.equinox.weaving.adaptors.WeavingAdaptor.weaveClass(Unknown Source)
  at org.eclipse.equinox.weaving.hooks.WeavingHook.processClass(Unknown Source)
  at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.defineClass(ClasspathManager.java:600)
  at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findClassImpl(ClasspathManager.java:568)
  at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClassImpl(ClasspathManager.java:492)
  at org.eclipse.osgi.baseadaptor.loader.ClasspathManager.findLocalClass(ClasspathManager.java:465)
  at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.findLocalClass(DefaultClassLoader.java:216)
  at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:395)
  at org.eclipse.osgi.internal.loader.SingleSourcePackage.loadClass(SingleSourcePackage.java:35)
  at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:461)
  at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:421)
  at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:412)
  at org.eclipse.osgi.internal.baseadaptor.DefaultClassLoader.loadClass(DefaultClassLoader.java:107)
  at java.lang.ClassLoader.loadClass(ClassLoader.java:690)
  at java.lang.J9VMInternals.verifyImpl(Native Method)
  at java.lang.J9VMInternals.verify(J9VMInternals.java:93)
  at java.lang.J9VMInternals.initialize(J9VMInternals.java:170)
  at java.lang.J9VMInternals.newInstanceImpl(Native Method)
  at java.lang.Class.newInstance(Class.java:1600)
  at org.eclipse.osgi.framework.internal.core.AbstractBundle.loadBundleActivator(AbstractBundle.java:167)
  ... 122 more
  </code></pre>