Bug 49182 What should canceling setRawClasspath do ?
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/BuildPathsPropertyPage.java
}
		return null;
	}
	
	private boolean isJavaProject(IProject proj) {
		try {
			return proj.hasNature(JavaCore.NATURE_ID);
		} catch (CoreException e) {
			JavaPlugin.log(e);
		}
		return false;
	}
	
	/*
	 * @see IPreferencePage#performOk
	 */
	public boolean performOk() {
		if (fBuildPathsBlock != null) {
			getSettings().put(INDEX, fBuildPathsBlock.getPageIndex());
			
			Shell shell= getControl().getShell();
			IWorkspaceRunnable runnable= new IWorkspaceRunnable() {
				public void run(IProgressMonitor monitor)	throws CoreException, OperationCanceledException {
					fBuildPathsBlock.configureJavaProject(monitor);
				}
			};
			IRunnableWithProgress op= new WorkbenchRunnableAdapter(runnable, getProject());
			try {
				new ProgressMonitorDialog(shell).run(true, true, op);
			} catch (InvocationTargetException e) {