I am facing an issue every time I am saving something in java file. I know the error message is coming from gwt plug-in.
java.lang.NoClassDefFoundError: com/google/gdt/eclipse/suite/preferences/GdtPreferences
at com.google.gdt.eclipse.suite.ext.update.FeatureUpdateManager.checkForUpdates(FeatureUpdateManager.java:105)
at com.google.gdt.eclipse.suite.ext.builders.UpdateTriggerCompilationParticipant.isActive(UpdateTriggerCompilationParticipant.java:40)
at org.eclipse.jdt.internal.core.JavaModelManager$CompilationParticipants.getCompilationParticipants(JavaModelManager.java:339)
at org.eclipse.jdt.internal.core.builder.JavaBuilder.initializeBuilder(JavaBuilder.java:587)
at org.eclipse.jdt.internal.core.builder.JavaBuilder.build(JavaBuilder.java:167)
at org.eclipse.core.internal.events.BuildManager$2.run(BuildManager.java:733)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:206)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:246)
at org.eclipse.core.internal.events.BuildManager$1.run(BuildManager.java:299)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.internal.events.BuildManager.basicBuild(BuildManager.java:302)
at org.eclipse.core.internal.events.BuildManager.basicBuildLoop(BuildManager.java:358)
at org.eclipse.core.internal.events.BuildManager.build(BuildManager.java:381)
at org.eclipse.core.internal.events.AutoBuildJob.doBuild(AutoBuildJob.java:143)
at org.eclipse.core.internal.events.AutoBuildJob.run(AutoBuildJob.java:241)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:53)
Workaround solution that may work:
Close all projects, close eclipse.
Start eclipse using, "eclipse -clean" option.
You can try repeating the process 2-3 times, if it does not work first time.
Not sure of the exact reason why this appears.