How to fix Eclipse and PreferenceConverter exception

I'm running Linux Mint on my desktop and I recently updated my eclipse version to new Juno. After that the Eclipse sometimes doesn't want to start and I end up with frozen tiny dialog without any content which I'm not able to close and have to kill it. The issue lies somewhere deep in preferences of your workspace when eclipse sometimes can't load your cached data. If something like this is happening to you as well try to check the log file of your current eclipse profile which you can find in YOUR_WORKSPACE/.metadata/.log - if you see some thing like the error below at the very bottom of this file then you are experiencing the same bug.

java.lang.NoClassDefFoundError: Could not initialize class org.eclipse.jface.preference.PreferenceConverter at org.eclipse.ui.internal.themes.ThemeElementHelper.installFont(ThemeElementHelper.java:103) at org.eclipse.ui.internal.themes.ThemeElementHelper.populateRegistry(ThemeElementHelper.java:59) at org.eclipse.ui.internal.Workbench$27.runWithException(Workbench.java:1550) at org.eclipse.ui.internal.StartupThreading$StartupRunnable.run(StartupThreading.java:31) at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135) at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:3529) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3182) at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2478) at org.eclipse.ui.internal.Workbench.access$7(Workbench.java:2386) at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:583) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:540) 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:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) 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)

So how to get rid of this? First of all kill the eclipse if its still running with:

ps -ax | grep eclipsekill $id

And then delete the file which is breaking Eclipse:

rm YOUR_WORKSPACE/.metadata/.plugins/org.eclipse.core.resources/.snap

That's it - enjoy coding!