Bug 32893 Workspace Compatibility Problems 2.0 -> 2.1
Build 2.1 RC1 This PR collects problems related to opening a 2.0 workspace with 2.1.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/JavaPlugin.java
* <code>javaEditorTextHovers</code>.
	 *
	 * @since 2.1
	 */
	public static String ID_BESTMATCH_HOVER= "org.eclipse.jdt.ui.BestMatchHover"; 
	/**
	 * The id of the source code hover contributed for extension point
	 * <code>javaEditorTextHovers</code>.
	 *
	 * @since 2.1
	 */
	public static String ID_SOURCE_HOVER= "org.eclipse.jdt.ui.JavaSourceHover"; 
	/**
	 * The id of the javadoc hover contributed for extension point
	 * <code>javaEditorTextHovers</code>.
	 *
	 * @since 2.1
	 */
	public static String ID_JAVADOC_HOVER= "org.eclipse.jdt.ui.JavadocHover"; 
	/**
	 * The id of the problem hover contributed for extension point
	 * <code>javaEditorTextHovers</code>.
	 *
	 * @since 2.1
	 */
	public static String ID_PROBLEM_HOVER= "org.eclipse.jdt.ui.ProblemHover"; 
		
	private static JavaPlugin fgJavaPlugin;
	private CompilationUnitDocumentProvider fCompilationUnitDocumentProvider;
	private ClassFileDocumentProvider fClassFileDocumentProvider;