Not able to start STS - eclipse

Question

Am not able to start my STS 3.3. It is failing to start by giving following exception
!ENTRY org.eclipse.osgi 4 0 2013-09-30 10:22:40.079
!MESSAGE Application error
!STACK 1
org.eclipse.core.runtime.CoreException: Plug-in "org.eclipse.ui.ide.application" was unable to instantiate class "org.eclipse.ui.internal.ide.application.IDEApplication".
at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.throwException(RegistryStrategyOSGI.java:194)
at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:188)
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.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:191)
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:354)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:181)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:636)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:591)
at org.eclipse.equinox.launcher.Main.run(Main.java:1450)
at org.eclipse.equinox.launcher.Main.main(Main.java:1426)
Caused by: java.lang.NoClassDefFoundError: org/eclipse/ui/application/WorkbenchAdvisor
at java.lang.Class.getDeclaredConstructors0(Native Method)
at java.lang.Class.privateGetDeclaredConstructors(Class.java:2483)
at java.lang.Class.getConstructor0(Class.java:2793)
at java.lang.Class.newInstance(Class.java:345)
at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension(RegistryStrategyOSGI.java:184)
... 16 more
Caused by: java.lang.ClassNotFoundException: org.eclipse.ui.application.WorkbenchAdvisor cannot be found by org.eclipse.ui.ide.application_1.0.400.v20130326-1250
at org.eclipse.osgi.internal.loader.BundleLoader.findClassInternal(BundleLoader.java:501)
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:357)
... 21 more
What is the problem here?

Answer 1

This is often a problem with temporary files saved by plugins. These steps should help you out:
Check YOUR_WORKSPACE/.metadata/.plugins/org.eclipse.jdt.core/ There are a lot of index files. Sometimes it helps to delete them. Also start your eclipse with -clean.
According to your problem, I think you've moved some files from the filesystem, a new location prehaps, that's causing this error. Try checking them.
Refresh all your projects.
Try creating a new workspace and check.
If nothing works, try re-installing it.
Also, if you decide not to go with STS, you can always use Eclipse IDE with STS plugin.
Hope it helps. :)