NullPointerException throws out while decompiling Java's Exception class.

[liangdefeng]

@cnfree, Could you help to have a check to see what's problem in the latest release of Eclipse Class Decompiler?

1. Eclipse Class Decompiler Version: 2.9.2 Build id: 20170623

2. Error info.

   / Eclipse Class Decompiler plugin, Copyright (c) 2017 Chen Chao. /

/* DECOMPILATION REPORT

Decompiled from: /usr/lib/jvm/java-1.8.0-openjdk-1.8.0.131-3.b12.el7_3.x86_64/jre/lib/rt.jar
Total time: 0 ms

Caught exceptions:

java.lang.NullPointerException at org.sf.feeling.decompiler.fernflower.FernFlowerDecompiler.deltree(FernFlowerDecompiler.java:156) at org.sf.feeling.decompiler.fernflower.FernFlowerDecompiler.decompileFromArchive(FernFlowerDecompiler.java:143) at org.sf.feeling.decompiler.editor.BaseDecompilerSourceMapper.decompile(BaseDecompilerSourceMapper.java:425) at org.sf.feeling.decompiler.editor.BaseDecompilerSourceMapper.findSource(BaseDecompilerSourceMapper.java:183) at org.sf.feeling.decompiler.editor.DecompilerSourceMapper.findSource(DecompilerSourceMapper.java:74) at org.sf.feeling.decompiler.editor.JavaDecompilerClassFileEditor.doOpenBuffer(JavaDecompilerClassFileEditor.java:131) at org.sf.feeling.decompiler.editor.JavaDecompilerClassFileEditor.doOpenBuffer(JavaDecompilerClassFileEditor.java:104) at org.sf.feeling.decompiler.editor.JavaDecompilerClassFileEditor.doOpenBuffer(JavaDecompilerClassFileEditor.java:96) at org.sf.feeling.decompiler.editor.JavaDecompilerClassFileEditor.doSetInput(JavaDecompilerClassFileEditor.java:463) at org.eclipse.ui.texteditor.AbstractTextEditor$5.run(AbstractTextEditor.java:3154) at org.eclipse.jface.operation.ModalContext.runInCurrentThread(ModalContext.java:437) at org.eclipse.jface.operation.ModalContext.run(ModalContext.java:353) at org.eclipse.ui.internal.WorkbenchWindow$14.run(WorkbenchWindow.java:2184) at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70) at org.eclipse.ui.internal.WorkbenchWindow.run(WorkbenchWindow.java:2180) at org.eclipse.ui.texteditor.AbstractTextEditor.internalInit(AbstractTextEditor.java:3172) at org.eclipse.ui.texteditor.AbstractTextEditor.init(AbstractTextEditor.java:3197) at org.eclipse.ui.internal.EditorReference.initialize(EditorReference.java:362) at org.eclipse.ui.internal.e4.compatibility.CompatibilityPart.create(CompatibilityPart.java:318) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.eclipse.e4.core.internal.di.MethodRequestor.execute(MethodRequestor.java:55) at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:966) at org.eclipse.e4.core.internal.di.InjectorImpl.processAnnotated(InjectorImpl.java:931) at org.eclipse.e4.core.internal.di.InjectorImpl.inject(InjectorImpl.java:151) at org.eclipse.e4.core.internal.di.InjectorImpl.internalMake(InjectorImpl.java:375) at org.eclipse.e4.core.internal.di.InjectorImpl.make(InjectorImpl.java:294) at org.eclipse.e4.core.contexts.ContextInjectionFactory.make(ContextInjectionFactory.java:162) at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.createFromBundle(ReflectionContributionFactory.java:105) at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.doCreate(ReflectionContributionFactory.java:74) at org.eclipse.e4.ui.internal.workbench.ReflectionContributionFactory.create(ReflectionContributionFactory.java:56) at org.eclipse.e4.ui.workbench.renderers.swt.ContributedPartRenderer.createWidget(ContributedPartRenderer.java:129) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createWidget(PartRenderingEngine.java:975) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:651) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.safeCreateGui(PartRenderingEngine.java:757) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.access$0(PartRenderingEngine.java:728) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$2.run(PartRenderingEngine.java:722) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.createGui(PartRenderingEngine.java:706) at org.eclipse.e4.ui.internal.workbench.PartServiceImpl$1.handleEvent(PartServiceImpl.java:104) at org.eclipse.e4.ui.services.internal.events.UIEventHandler$1.run(UIEventHandler.java:40) at org.eclipse.swt.widgets.Synchronizer.syncExec(Synchronizer.java:233) at org.eclipse.ui.internal.UISynchronizer.syncExec(UISynchronizer.java:145) at org.eclipse.swt.widgets.Display.syncExec(Display.java:5414) at org.eclipse.e4.ui.internal.workbench.swt.E4Application$1.syncExec(E4Application.java:211) at org.eclipse.e4.ui.services.internal.events.UIEventHandler.handleEvent(UIEventHandler.java:36) at org.eclipse.equinox.internal.event.EventHandlerWrapper.handleEvent(EventHandlerWrapper.java:201) at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:197) at org.eclipse.equinox.internal.event.EventHandlerTracker.dispatchEvent(EventHandlerTracker.java:1) at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230) at org.eclipse.osgi.framework.eventmgr.ListenerQueue.dispatchEventSynchronous(ListenerQueue.java:148) at org.eclipse.equinox.internal.event.EventAdminImpl.dispatchEvent(EventAdminImpl.java:135) at org.eclipse.equinox.internal.event.EventAdminImpl.sendEvent(EventAdminImpl.java:78) at org.eclipse.equinox.internal.event.EventComponent.sendEvent(EventComponent.java:39) at org.eclipse.e4.ui.services.internal.events.EventBroker.send(EventBroker.java:94) at org.eclipse.e4.ui.internal.workbench.UIEventPublisher.notifyChanged(UIEventPublisher.java:60) at org.eclipse.emf.common.notify.impl.BasicNotifierImpl.eNotify(BasicNotifierImpl.java:374) at org.eclipse.e4.ui.model.application.ui.impl.ElementContainerImpl.setSelectedElement(ElementContainerImpl.java:173) at org.eclipse.e4.ui.internal.workbench.ModelServiceImpl.showElementInWindow(ModelServiceImpl.java:617) at org.eclipse.e4.ui.internal.workbench.ModelServiceImpl.bringToTop(ModelServiceImpl.java:581) at org.eclipse.e4.ui.internal.workbench.PartServiceImpl.delegateBringToTop(PartServiceImpl.java:770) at org.eclipse.e4.ui.internal.workbench.PartServiceImpl.showPart(PartServiceImpl.java:1211) at org.eclipse.ui.internal.WorkbenchPage.busyOpenEditor(WorkbenchPage.java:3261) at org.eclipse.ui.internal.WorkbenchPage.access$25(WorkbenchPage.java:3176) at org.eclipse.ui.internal.WorkbenchPage$10.run(WorkbenchPage.java:3158) at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:70) at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:3153) at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:3117) at org.eclipse.ui.internal.WorkbenchPage.openEditor(WorkbenchPage.java:3107) at org.eclipse.jdt.internal.ui.javaeditor.EditorUtility.openInEditor(EditorUtility.java:373) at org.eclipse.jdt.internal.ui.javaeditor.EditorUtility.openInEditor(EditorUtility.java:179) at org.eclipse.jdt.ui.actions.OpenAction.run(OpenAction.java:256) at org.eclipse.jdt.ui.actions.OpenAction.run(OpenAction.java:171) at org.eclipse.jdt.ui.actions.SelectionDispatchAction.dispatchRun(SelectionDispatchAction.java:275) at org.eclipse.jdt.ui.actions.SelectionDispatchAction.run(SelectionDispatchAction.java:249) at org.eclipse.jface.action.Action.runWithEvent(Action.java:473) at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:565) at org.eclipse.jface.action.ActionContributionItem.lambda$4(ActionContributionItem.java:397) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Display.sendEvent(Display.java:5227) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1340) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4561) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:4151) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$4.run(PartRenderingEngine.java:1121) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1022) at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:150) at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:693) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:336) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:610) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:148) at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:138) at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:134) at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:104) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:388) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:243) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:673) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:610) at org.eclipse.equinox.launcher.Main.run(Main.java:1519) at org.eclipse.equinox.launcher.Main.main(Main.java:1492)

*/

[cnfree]

The decompiler plugin output the decompiled result at the directory TEMP_DIR. When cleaning the TEMP_DIR, the TEMP_DIR doesn't have any files, so it throws the NullPointerException.

store.setDefault( TEMP_DIR,
                System.getProperty( "java.io.tmpdir" ) //$NON-NLS-1$
                        + File.separator
                        + ".org.sf.feeling.decompiler" ); //$NON-NLS-1$

Does the decompiler have the write permission at TEMP_DIR?

[liangdefeng]

Thanks @cnfree. I would like to know where can I find the TEMP_DIR which the plugin output the result? My OS is CentOS 7.3, and the account I am using isn't an root user and doesn't have full access to all files.

[liangdefeng]

I find where the TEMP_DIR is in my environment. It is /tmp/, my account has read and write access right to that folder. I still has problem in decompiling. I will write down the detail later for your investigation.

[liangdefeng]

As the exception is gone, I close the issue.

[cnfree]

I used a guest user and tested the latest version v2.9.4 on ubuntu, but couldn't reproduce this issue.

Does the version v2.9.4 on your machine still has this problem?

[liangdefeng]

Thanks @cnfree. v2.9.4 can't decompile some classes, but it doesn't throw exceptions. The issue turns out to be the folder's access right problem.