Eclipse has suddenly broken

[Fluorescent Flamingo]

Yesterday Eclipse suddenly stopped working for me, and I don't know why. I didn't mess around with anything, and I've never had this problem before in years of using the software.

 

When I try to close the program it gives this error:

 

An error has occurred. See error log for more details.
Could not initialize class com.sun.org.apache.xml.internal.serializer.Encodings

 

Upon checking the error log:

Spoiler

!ENTRY org.eclipse.ui.workbench 4 2 2020-05-05 23:38:36.080
!MESSAGE Problems occurred when invoking code from plug-in: "org.eclipse.ui.workbench".
!STACK 0
java.lang.NoClassDefFoundError: Could not initialize class com.sun.org.apache.xml.internal.serializer.Encodings
	at com.sun.org.apache.xml.internal.serializer.ToStream.<init>(Unknown Source)
	at com.sun.org.apache.xml.internal.serializer.ToXMLStream.<init>(Unknown Source)
	at com.sun.org.apache.xml.internal.serializer.ToUnknownStream.<init>(Unknown Source)
	at com.sun.org.apache.xalan.internal.xsltc.runtime.output.TransletOutputHandlerFactory.getSerializationHandler(Unknown Source)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.getOutputHandler(Unknown Source)
	at com.sun.org.apache.xalan.internal.xsltc.trax.TransformerImpl.transform(Unknown Source)
	at org.eclipse.buildship.core.internal.preferences.BuildCommandConverter.toXml(BuildCommandConverter.java:84)
	at org.eclipse.buildship.core.internal.preferences.BuildCommandConverter.toXml(BuildCommandConverter.java:146)
	at org.eclipse.buildship.core.internal.preferences.PersistentModelConverter$7.apply(PersistentModelConverter.java:105)
	at org.eclipse.buildship.core.internal.preferences.PersistentModelConverter$7.apply(PersistentModelConverter.java:101)
	at org.eclipse.buildship.core.internal.preferences.PersistentModelConverter.storeValue(PersistentModelConverter.java:222)
	at org.eclipse.buildship.core.internal.preferences.PersistentModelConverter.toProperties(PersistentModelConverter.java:101)
	at org.eclipse.buildship.core.internal.preferences.DefaultModelPersistence.persistPrefsChecked(DefaultModelPersistence.java:160)
	at org.eclipse.buildship.core.internal.preferences.DefaultModelPersistence.persistPrefs(DefaultModelPersistence.java:146)
	at org.eclipse.buildship.core.internal.preferences.DefaultModelPersistence.persistAllProjectPrefs(DefaultModelPersistence.java:139)
	at org.eclipse.buildship.core.internal.preferences.DefaultModelPersistence.onEvent(DefaultModelPersistence.java:89)
	at org.eclipse.buildship.core.internal.event.DefaultListenerRegistry.dispatch(DefaultListenerRegistry.java:50)
	at org.eclipse.buildship.ui.internal.workspace.ShutdownListener.preShutdown(ShutdownListener.java:27)
	at org.eclipse.ui.internal.Workbench$4.run(Workbench.java:954)
	at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:45)
	at org.eclipse.ui.internal.JFaceUtil.lambda$0(JFaceUtil.java:47)
	at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:174)
	at org.eclipse.ui.internal.Workbench.firePreShutdown(Workbench.java:951)
	at org.eclipse.ui.internal.Workbench.busyClose(Workbench.java:1080)
	at org.eclipse.ui.internal.Workbench.lambda$4(Workbench.java:1426)
	at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:72)
	at org.eclipse.ui.internal.Workbench.close(Workbench.java:1426)
	at org.eclipse.ui.internal.Workbench.close(Workbench.java:1402)
	at org.eclipse.ui.internal.WorkbenchWindow.busyClose(WorkbenchWindow.java:1744)
	at org.eclipse.ui.internal.WorkbenchWindow.lambda$3(WorkbenchWindow.java:1773)
	at org.eclipse.swt.custom.BusyIndicator.showWhile(BusyIndicator.java:72)
	at org.eclipse.ui.internal.WorkbenchWindow.close(WorkbenchWindow.java:1773)
	at org.eclipse.ui.internal.WorkbenchWindow.close(WorkbenchWindow.java:1782)
	at org.eclipse.ui.internal.WorkbenchWindow$3.close(WorkbenchWindow.java:523)
	at org.eclipse.e4.ui.workbench.renderers.swt.WBWRenderer.lambda$4(WBWRenderer.java:578)
	at org.eclipse.swt.events.ShellListener$2.shellClosed(ShellListener.java:102)
	at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:102)
	at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:89)
	at org.eclipse.swt.widgets.Display.sendEvent(Display.java:4105)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1037)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1061)
	at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1046)
	at org.eclipse.swt.widgets.Decorations.closeWidget(Decorations.java:269)
	at org.eclipse.swt.widgets.Decorations.WM_CLOSE(Decorations.java:1552)
	at org.eclipse.swt.widgets.Control.windowProc(Control.java:4720)
	at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:335)
	at org.eclipse.swt.widgets.Decorations.windowProc(Decorations.java:1480)
	at org.eclipse.swt.widgets.Shell.windowProc(Shell.java:2100)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:4749)
	at org.eclipse.swt.internal.win32.OS.DefWindowProc(Native Method)
	at org.eclipse.swt.widgets.Shell.callWindowProc(Shell.java:508)
	at org.eclipse.swt.widgets.Control.windowProc(Control.java:4819)
	at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:335)
	at org.eclipse.swt.widgets.Decorations.windowProc(Decorations.java:1480)
	at org.eclipse.swt.widgets.Shell.windowProc(Shell.java:2100)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:4749)
	at org.eclipse.swt.internal.win32.OS.DefWindowProc(Native Method)
	at org.eclipse.swt.widgets.Shell.callWindowProc(Shell.java:508)
	at org.eclipse.swt.widgets.Control.windowProc(Control.java:4819)
	at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:335)
	at org.eclipse.swt.widgets.Decorations.windowProc(Decorations.java:1480)
	at org.eclipse.swt.widgets.Shell.windowProc(Shell.java:2100)
	at org.eclipse.swt.widgets.Display.windowProc(Display.java:4749)
	at org.eclipse.swt.internal.win32.OS.DispatchMessage(Native Method)
	at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3522)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$5.run(PartRenderingEngine.java:1160)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
	at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:1049)
	at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:155)
	at org.eclipse.ui.internal.Workbench.lambda$3(Workbench.java:658)
	at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:338)
	at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:557)
	at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:154)
	at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:150)
	at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:203)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:137)
	at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:107)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:401)
	at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:255)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
	at java.lang.reflect.Method.invoke(Unknown Source)
	at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:657)
	at org.eclipse.equinox.launcher.Main.basicRun(Main.java:594)
	at org.eclipse.equinox.launcher.Main.run(Main.java:1447)

 

 

I can't close Eclipse at all without using Task Manager now.

 

This is only the most visible of many bugs and errors that have suddenly popped up in the program. There are lots of other dialog boxes that pop up with these similar errors when I try to do various tasks. Such as: At first I could still run my mod from inside Eclipse, but now I get an InvocationTargetException when I try to view the run configurations and cannot select runClient.

 

What I have tried:

• deleting the .metadata folder in my workspace and reopening Eclipse;
• deleting the entire ForgeGradle project, rerunning ForgeGradle setup, reimporting my sources and recreating the project;
• completely uninstalling and redownloading Eclipse, and then recreating the project.

 

None of these have worked. I'd really appreciate some help!

Edited May 5, 2020 by Fluorescent Flamingo

[Vinyarion]

Issue has been resolved by cleaning out old Java installations from environment variables