问题
I am developing a plugin for eclipse and from time to time (yes, sometimes it works, sometimes not. Then I have to clean the project and restart everything.) I get the following error when activating it:
Caused by: java.lang.ClassNotFoundException: An error occurred while automatically activating bundle DeepRefactoring (501).
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.loader.ModuleClassLoader.loadClass(ModuleClassLoader.java:160)
at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
at org.eclipse.osgi.internal.framework.EquinoxBundle.loadClass(EquinoxBundle.java:568)
at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:174)
... 49 more
Caused by: org.osgi.framework.BundleException: Error starting module.
at org.eclipse.osgi.container.Module.doStart(Module.java:580)
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)
... 59 more
Caused by: java.lang.Error: Unresolved compilation problems:
The import org.eclipse cannot be resolved
The import org.eclipse cannot be resolved
The import org.osgi cannot be resolved
AbstractUIPlugin cannot be resolved to a type
BundleContext cannot be resolved to a type
BundleContext cannot be resolved to a type
ImageDescriptor cannot be resolved to a type
The method imageDescriptorFromPlugin(String, String) is undefined for the type Activator
at deeprefactoring.Activator.<init>(Activator.java:7)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:526)
at java.lang.Class.newInstance(Class.java:379)
at org.eclipse.osgi.internal.framework.BundleContextImpl.loadBundleActivator(BundleContextImpl.java:755)
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)
... 62 more
All libraries are present (there are no compilation errors shown in the project).
Do you have any ideas where this could come from?
EDIT:
OK, so I kind of found the solution: I had the plug-in project not only in my original workspace but also in the runtime workspace. For some reason, there (in the runtime workspace) it was not possible to compile the projects, it had errors. After closing the instance the project somehow remembered that it had errors and therefore it was now also impossible to run from the original workspace. Cleaning the project afterwards seems to work. Other solutions could be: removing or closing the project in the runtime workspace or disable automatic build there.
来源：https://stackoverflow.com/questions/27908211/compilation-error-when-starting-eclipse-plugin-cant-find-libraries-even-though