Could not set class path variable error in eclipse when trying to add new variable in classpath

Question

I am trying to add a new variable in classpath in eclipse.Right click on project -- > Build Path --> Configure Build Path --> Libraries Tab. From the right button panel,I selected Add Variable --> Configure Variables -->New.I am adding a new variable and when then eclipse gives a popup asking to have rebuild for changes to take effect.When I click OK,i get error 'Could Not Set Class Path Variables..See error logs for more details'.I checked in 'Error Log,I found:'Internal Error'.Double cliking on it Shows below exception: Java Model Exception: Core Exception [code 0] PWMATRIX_HOME variable is not defined! at org.eclipse.jdt.internal.core.JavaModelManager.initializeContainer(JavaModelManager.java:2887) at org.eclipse.jdt.internal.core.JavaModelManager.getClasspathContainer(JavaModelManager.java:1877) at org.eclipse.jdt.core.JavaCore.getClasspathContainer(JavaCore.java:2798) at org.eclipse.jdt.internal.core.JavaProject.resolveClasspath(JavaProject.java:2674) at org.eclipse.jdt.internal.core.JavaProject.resolveClasspath(JavaProject.java:2838) at org.eclipse.jdt.internal.core.JavaProject.getResolvedClasspath(JavaProject.java:1943) at org.eclipse.jdt.internal.core.JavaProject.buildStructure(JavaProject.java:461) at org.eclipse.jdt.internal.core.Openable.generateInfos(Openable.java:258) at org.eclipse.jdt.internal.core.JavaElement.openWhenClosed(JavaElement.java:518) at org.eclipse.jdt.internal.core.JavaElement.getElementInfo(JavaElement.java:255) at org.eclipse.jdt.internal.core.JavaElement.getElementInfo(JavaElement.java:241) at org.eclipse.jdt.internal.core.JavaElement.getChildren(JavaElement.java:196) at org.eclipse.jdt.internal.core.JavaProject.getPackageFragmentRoots(JavaProject.java:1831) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage.getSelectedPackageFragmentRoot(LibrariesWorkbookPage.java:369) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage.updateEnabledState(LibrariesWorkbookPage.java:604) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage.libaryPageSelectionChanged(LibrariesWorkbookPage.java:597) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage.access$1(LibrariesWorkbookPage.java:596) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage$LibrariesAdapter.selectionChanged(LibrariesWorkbookPage.java:203) at org.eclipse.jdt.internal.ui.wizards.dialogfields.TreeListDialogField.doListSelected(TreeListDialogField.java:924) at org.eclipse.jdt.internal.ui.wizards.dialogfields.TreeListDialogField$TreeViewerAdapter.selectionChanged(TreeListDialogField.java:909) at org.eclipse.jface.viewers.Viewer$2.run(Viewer.java:164) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42) at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:49) at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175) at org.eclipse.jface.viewers.Viewer.fireSelectionChanged(Viewer.java:162) at org.eclipse.jface.viewers.StructuredViewer.updateSelection(StructuredViewer.java:2188) at org.eclipse.jface.viewers.StructuredViewer.handleSelect(StructuredViewer.java:1211) at org.eclipse.jface.viewers.StructuredViewer$4.widgetSelected(StructuredViewer.java:1241) at org.eclipse.jface.util.OpenStrategy.fireSelectionEvent(OpenStrategy.java:239) at org.eclipse.jface.util.OpenStrategy.access$4(OpenStrategy.java:233) at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:403) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4165) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3754) at org.eclipse.jface.window.Window.runEventLoop(Window.java:825) at org.eclipse.jface.window.Window.open(Window.java:801) at org.eclipse.jdt.internal.ui.wizards.buildpaths.newsourcepage.ConfigureBuildPathAction.run(ConfigureBuildPathAction.java:88) at org.eclipse.jface.action.Action.runWithEvent(Action.java:498) at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:584) at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:501) at org.eclipse.jface.action.ActionContributionItem$5.handleEvent(ActionContributionItem.java:411) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4165) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3754) at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2696) at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2660) at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2494) at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:674) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:667) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149) at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123) 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:344) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179) 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:622) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577) at org.eclipse.equinox.launcher.Main.run(Main.java:1410) at org.eclipse.equinox.launcher.Main.main(Main.java:1386) Caused by: org.eclipse.core.runtime.CoreException: PWMATRIX_HOME variable is not defined! at com.ssc.cdt.eclipse.initializers.WSFContainerInitializer.getExtraAttrubutes(WSFContainerInitializer.java:146) at com.ssc.cdt.eclipse.initializers.WSFContainerInitializer.getCloudFrameworkJars(WSFContainerInitializer.java:178) at com.ssc.cdt.eclipse.initializers.WSFContainerInitializer.initialize(WSFContainerInitializer.java:188) at org.eclipse.jdt.internal.core.JavaModelManager.initializeContainer(JavaModelManager.java:2863) at org.eclipse.jdt.internal.core.JavaModelManager.getClasspathContainer(JavaModelManager.java:1877) at org.eclipse.jdt.core.JavaCore.getClasspathContainer(JavaCore.java:2798) at org.eclipse.jdt.internal.core.JavaProject.resolveClasspath(JavaProject.java:2674) at org.eclipse.jdt.internal.core.JavaProject.resolveClasspath(JavaProject.java:2838) at org.eclipse.jdt.internal.core.JavaProject.getResolvedClasspath(JavaProject.java:1943) at org.eclipse.jdt.internal.core.JavaProject.buildStructure(JavaProject.java:461) at org.eclipse.jdt.internal.core.Openable.generateInfos(Openable.java:258) at org.eclipse.jdt.internal.core.JavaElement.openWhenClosed(JavaElement.java:518) at org.eclipse.jdt.internal.core.JavaElement.getElementInfo(JavaElement.java:255) at org.eclipse.jdt.internal.core.JavaElement.getElementInfo(JavaElement.java:241) at org.eclipse.jdt.internal.core.JavaElement.getChildren(JavaElement.java:196) at org.eclipse.jdt.internal.core.JavaProject.getPackageFragmentRoots(JavaProject.java:1831) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage.getSelectedPackageFragmentRoot(LibrariesWorkbookPage.java:369) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage.updateEnabledState(LibrariesWorkbookPage.java:604) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage.libaryPageSelectionChanged(LibrariesWorkbookPage.java:597) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage.access$1(LibrariesWorkbookPage.java:596) at org.eclipse.jdt.internal.ui.wizards.buildpaths.LibrariesWorkbookPage$LibrariesAdapter.selectionChanged(LibrariesWorkbookPage.java:203) at org.eclipse.jdt.internal.ui.wizards.dialogfields.TreeListDialogField.doListSelected(TreeListDialogField.java:924) at org.eclipse.jdt.internal.ui.wizards.dialogfields.TreeListDialogField$TreeViewerAdapter.selectionChanged(TreeListDialogField.java:909) at org.eclipse.jface.viewers.Viewer$2.run(Viewer.java:164) at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42) at org.eclipse.ui.internal.JFaceUtil$1.run(JFaceUtil.java:49) at org.eclipse.jface.util.SafeRunnable.run(SafeRunnable.java:175) at org.eclipse.jface.viewers.Viewer.fireSelectionChanged(Viewer.java:162) at org.eclipse.jface.viewers.StructuredViewer.updateSelection(StructuredViewer.java:2188) at org.eclipse.jface.viewers.StructuredViewer.handleSelect(StructuredViewer.java:1211) at org.eclipse.jface.viewers.StructuredViewer$4.widgetSelected(StructuredViewer.java:1241) at org.eclipse.jface.util.OpenStrategy.fireSelectionEvent(OpenStrategy.java:239) at org.eclipse.jface.util.OpenStrategy.access$4(OpenStrategy.java:233) at org.eclipse.jface.util.OpenStrategy$1.handleEvent(OpenStrategy.java:403) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4165) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3754) at org.eclipse.jface.window.Window.runEventLoop(Window.java:825) at org.eclipse.jface.window.Window.open(Window.java:801) at org.eclipse.jdt.internal.ui.wizards.buildpaths.newsourcepage.ConfigureBuildPathAction.run(ConfigureBuildPathAction.java:88) at org.eclipse.jface.action.Action.runWithEvent(Action.java:498) at org.eclipse.jface.action.ActionContributionItem.handleWidgetSelection(ActionContributionItem.java:584) at org.eclipse.jface.action.ActionContributionItem.access$2(ActionContributionItem.java:501) at org.eclipse.jface.action.ActionContributionItem$5.handleEvent(ActionContributionItem.java:411) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4165) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3754) at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2696) at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2660) at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2494) at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:674) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:667) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149) at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123) 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:344) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179) 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:622) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577) at org.eclipse.equinox.launcher.Main.run(Main.java:1410) at org.eclipse.equinox.launcher.Main.main(Main.java:1386) I am not able to get why these exceptions are occurring and how to resolve it. Expecting a solution.thanks.

Answer 1

Try setting them from Window --> Preference --> Classpath Variables. Close your project folders before that.