java.lang.NullPointerException : Application ID must not be null 异常

Question

我刚刚在 eclipse 插件开发期间遇到了这个错误。

当通过“Launch eclipse application”测试插件时，上述 NullPointerException 弹出了约 90.000 行的堆栈跟踪，插件在 5 分钟前运行得非常好。在网上搜索此异常时，我没有发现任何有用的信息。

堆栈跟踪甚至没有显示来 self 的插件的文件，仅列出了 eclipse 内部文件。

这里是堆栈跟踪的一部分(整个跟踪太大了，不能在这里添加)

org.osgi.framework.BundleException: Error loading bundle activator.
    at org.eclipse.osgi.internal.framework.BundleContextImpl.start(BundleContextImpl.java:711)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.startWorker0(EquinoxBundle.java:936)
    at org.eclipse.osgi.internal.framework.EquinoxBundle$EquinoxModule.startWorker(EquinoxBundle.java:319)
    at org.eclipse.osgi.container.Module.doStart(Module.java:571)
    at org.eclipse.osgi.container.Module.start(Module.java:439)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1582)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.incStartLevel(ModuleContainer.java:1562)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.doContainerStartLevel(ModuleContainer.java:1533)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1476)
    at org.eclipse.osgi.container.ModuleContainer$ContainerStartLevel.dispatchEvent(ModuleContainer.java:1)
    at org.eclipse.osgi.framework.eventmgr.EventManager.dispatchEvent(EventManager.java:230)
    at org.eclipse.osgi.framework.eventmgr.EventManager$EventThread.run(EventManager.java:340)
Caused by: java.lang.ClassNotFoundException: An error occurred while automatically activating bundle org.eclipse.core.runtime (119).
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:116)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:531)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:324)
    at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:320)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:395)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.loadBundleActivator(BundleContextImpl.java:754)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.start(BundleContextImpl.java:706)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.startWorker0(EquinoxBundle.java:936)
    at org.eclipse.osgi.internal.framework.EquinoxBundle$EquinoxModule.startWorker(EquinoxBundle.java:319)
    at org.eclipse.osgi.container.Module.doStart(Module.java:571)
    at org.eclipse.osgi.container.Module.start(Module.java:439)
    at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:454)
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:531)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:324)
    at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:320)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:395)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.loadClass(EquinoxBundle.java:568)
    at org.eclipse.equinox.internal.ds.model.ServiceComponent.createInstance(ServiceComponent.java:493)
    at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.createInstance(ServiceComponentProp.java:270)
    at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.build(ServiceComponentProp.java:331)
    at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponent(InstanceProcess.java:620)
    at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponents(InstanceProcess.java:197)
    at org.eclipse.equinox.internal.ds.Resolver.buildNewlySatisfied(Resolver.java:473)
    at org.eclipse.equinox.internal.ds.Resolver.enableComponents(Resolver.java:217)
    at org.eclipse.equinox.internal.ds.SCRManager.performWork(SCRManager.java:816)
    at org.eclipse.equinox.internal.ds.SCRManager$QueuedJob.dispatch(SCRManager.java:783)
    at org.eclipse.equinox.internal.ds.WorkThread.run(WorkThread.java:89)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.osgi.framework.BundleException: Exception in org.eclipse.core.internal.runtime.PlatformActivator.start() of bundle org.eclipse.core.runtime.
    at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:792)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.start(BundleContextImpl.java:721)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.startWorker0(EquinoxBundle.java:936)
    at org.eclipse.osgi.internal.framework.EquinoxBundle$EquinoxModule.startWorker(EquinoxBundle.java:319)
    at org.eclipse.osgi.container.Module.doStart(Module.java:571)
    at org.eclipse.osgi.container.Module.start(Module.java:439)
    at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:454)
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107)
    ... 34 more
Caused by: java.lang.NoClassDefFoundError: org/eclipse/equinox/internal/app/CommandLineArgs
    at org.eclipse.core.internal.runtime.PlatformActivator.startAppContainer(PlatformActivator.java:47)
    at org.eclipse.core.internal.runtime.PlatformActivator.start(PlatformActivator.java:33)
    at org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:771)
    at org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:1)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:764)
    ... 41 more
Caused by: java.lang.ClassNotFoundException: An error occurred while automatically activating bundle org.eclipse.equinox.app (173).
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:116)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:531)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:324)
    at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:320)
    at org.eclipse.osgi.internal.loader.sources.SingleSourcePackage.loadClass(SingleSourcePackage.java:36)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:391)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 47 more
Caused by: org.osgi.framework.BundleException: Exception in org.eclipse.equinox.internal.app.Activator.start() of bundle org.eclipse.equinox.app.
    at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:792)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.start(BundleContextImpl.java:721)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.startWorker0(EquinoxBundle.java:936)
    at org.eclipse.osgi.internal.framework.EquinoxBundle$EquinoxModule.startWorker(EquinoxBundle.java:319)
    at org.eclipse.osgi.container.Module.doStart(Module.java:571)
    at org.eclipse.osgi.container.Module.start(Module.java:439)
    at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:454)
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107)
    ... 56 more
Caused by: java.lang.NullPointerException: Application ID must not be null!
    at org.osgi.service.application.ApplicationDescriptor.<init>(ApplicationDescriptor.java:128)
    at org.eclipse.equinox.internal.app.EclipseAppDescriptor.<init>(EclipseAppDescriptor.java:52)
    at org.eclipse.equinox.internal.app.EclipseAppContainer.createAppDescriptor(EclipseAppContainer.java:186)
    at org.eclipse.equinox.internal.app.EclipseAppContainer.registerAppDescriptors(EclipseAppContainer.java:272)
    at org.eclipse.equinox.internal.app.EclipseAppContainer.start(EclipseAppContainer.java:99)
    at org.eclipse.equinox.internal.app.Activator.addingService(Activator.java:134)
    at org.osgi.util.tracker.ServiceTracker$Tracked.customizerAdding(ServiceTracker.java:941)
    at org.osgi.util.tracker.ServiceTracker$Tracked.customizerAdding(ServiceTracker.java:1)
    at org.osgi.util.tracker.AbstractTracked.trackAdding(AbstractTracked.java:256)
    at org.osgi.util.tracker.AbstractTracked.trackInitial(AbstractTracked.java:183)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:318)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:261)
    at org.eclipse.equinox.internal.app.Activator.start(Activator.java:56)
    at org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:771)
    at org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:1)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:764)
    ... 63 more
Root exception:
java.lang.ClassNotFoundException: An error occurred while automatically activating bundle org.eclipse.core.runtime (119).
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:116)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:531)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:324)
    at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:320)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:395)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.loadBundleActivator(BundleContextImpl.java:754)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.start(BundleContextImpl.java:706)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.startWorker0(EquinoxBundle.java:936)
    at org.eclipse.osgi.internal.framework.EquinoxBundle$EquinoxModule.startWorker(EquinoxBundle.java:319)
    at org.eclipse.osgi.container.Module.doStart(Module.java:571)
    at org.eclipse.osgi.container.Module.start(Module.java:439)
    at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:454)
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:531)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:324)
    at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:320)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:395)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.loadClass(EquinoxBundle.java:568)
    at org.eclipse.equinox.internal.ds.model.ServiceComponent.createInstance(ServiceComponent.java:493)
    at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.createInstance(ServiceComponentProp.java:270)
    at org.eclipse.equinox.internal.ds.model.ServiceComponentProp.build(ServiceComponentProp.java:331)
    at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponent(InstanceProcess.java:620)
    at org.eclipse.equinox.internal.ds.InstanceProcess.buildComponents(InstanceProcess.java:197)
    at org.eclipse.equinox.internal.ds.Resolver.buildNewlySatisfied(Resolver.java:473)
    at org.eclipse.equinox.internal.ds.Resolver.enableComponents(Resolver.java:217)
    at org.eclipse.equinox.internal.ds.SCRManager.performWork(SCRManager.java:816)
    at org.eclipse.equinox.internal.ds.SCRManager$QueuedJob.dispatch(SCRManager.java:783)
    at org.eclipse.equinox.internal.ds.WorkThread.run(WorkThread.java:89)
    at java.lang.Thread.run(Thread.java:745)
Caused by: org.osgi.framework.BundleException: Exception in org.eclipse.core.internal.runtime.PlatformActivator.start() of bundle org.eclipse.core.runtime.
    at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:792)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.start(BundleContextImpl.java:721)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.startWorker0(EquinoxBundle.java:936)
    at org.eclipse.osgi.internal.framework.EquinoxBundle$EquinoxModule.startWorker(EquinoxBundle.java:319)
    at org.eclipse.osgi.container.Module.doStart(Module.java:571)
    at org.eclipse.osgi.container.Module.start(Module.java:439)
    at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:454)
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107)
    ... 34 more
Caused by: java.lang.NoClassDefFoundError: org/eclipse/equinox/internal/app/CommandLineArgs
    at org.eclipse.core.internal.runtime.PlatformActivator.startAppContainer(PlatformActivator.java:47)
    at org.eclipse.core.internal.runtime.PlatformActivator.start(PlatformActivator.java:33)
    at org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:771)
    at org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:1)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:764)
    ... 41 more
Caused by: java.lang.ClassNotFoundException: An error occurred while automatically activating bundle org.eclipse.equinox.app (173).
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:116)
    at org.eclipse.osgi.internal.loader.classpath.ClasspathManager.findLocalClass(ClasspathManager.java:531)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.findLocalClass(ModuleClassLoader.java:324)
    at org.eclipse.osgi.internal.loader.BundleLoader.findLocalClass(BundleLoader.java:320)
    at org.eclipse.osgi.internal.loader.sources.SingleSourcePackage.loadClass(SingleSourcePackage.java:36)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:391)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:345)
    at org.eclipse.osgi.internal.loader.BundleLoader.findClass(BundleLoader.java:337)
    at org.eclipse.osgi.internal.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 47 more
Caused by: org.osgi.framework.BundleException: Exception in org.eclipse.equinox.internal.app.Activator.start() of bundle org.eclipse.equinox.app.
    at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:792)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.start(BundleContextImpl.java:721)
    at org.eclipse.osgi.internal.framework.EquinoxBundle.startWorker0(EquinoxBundle.java:936)
    at org.eclipse.osgi.internal.framework.EquinoxBundle$EquinoxModule.startWorker(EquinoxBundle.java:319)
    at org.eclipse.osgi.container.Module.doStart(Module.java:571)
    at org.eclipse.osgi.container.Module.start(Module.java:439)
    at org.eclipse.osgi.framework.util.SecureAction.start(SecureAction.java:454)
    at org.eclipse.osgi.internal.hooks.EclipseLazyStarter.postFindLocalClass(EclipseLazyStarter.java:107)
    ... 56 more
Caused by: java.lang.NullPointerException: Application ID must not be null!
    at org.osgi.service.application.ApplicationDescriptor.<init>(ApplicationDescriptor.java:128)
    at org.eclipse.equinox.internal.app.EclipseAppDescriptor.<init>(EclipseAppDescriptor.java:52)
    at org.eclipse.equinox.internal.app.EclipseAppContainer.createAppDescriptor(EclipseAppContainer.java:186)
    at org.eclipse.equinox.internal.app.EclipseAppContainer.registerAppDescriptors(EclipseAppContainer.java:272)
    at org.eclipse.equinox.internal.app.EclipseAppContainer.start(EclipseAppContainer.java:99)
    at org.eclipse.equinox.internal.app.Activator.addingService(Activator.java:134)
    at org.osgi.util.tracker.ServiceTracker$Tracked.customizerAdding(ServiceTracker.java:941)
    at org.osgi.util.tracker.ServiceTracker$Tracked.customizerAdding(ServiceTracker.java:1)
    at org.osgi.util.tracker.AbstractTracked.trackAdding(AbstractTracked.java:256)
    at org.osgi.util.tracker.AbstractTracked.trackInitial(AbstractTracked.java:183)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:318)
    at org.osgi.util.tracker.ServiceTracker.open(ServiceTracker.java:261)
    at org.eclipse.equinox.internal.app.Activator.start(Activator.java:56)
    at org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:771)
    at org.eclipse.osgi.internal.framework.BundleContextImpl$3.run(BundleContextImpl.java:1)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.eclipse.osgi.internal.framework.BundleContextImpl.startActivator(BundleContextImpl.java:764)
    ... 63 more

Answer 1

看起来我自己造成了麻烦，删除了文件“plugin.xml”顶部的一行。这里是文件的正确开头:

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.4"?>
<plugin>
   <extension
           id="application"
         point="org.eclipse.core.runtime.applications">
...

如果缺少 id="application"，插件将产生所描述的异常。