Bug 54470 Eclipse should disallow usage of types defined in default package
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/wizards/NewTypeWizardPage.java
* Subclasses may extend this method to perform their own validation.
	 * </p>
	 * 
	 * @return the status of the validation
	 */
	protected IStatus superClassChanged() {
		StatusInfo status= new StatusInfo();
		IPackageFragmentRoot root= getPackageFragmentRoot();
		fSuperClassDialogField.enableButton(root != null);
		
		fSuperClass= null;
		
		String sclassName= getSuperClass();
		if (sclassName.length() == 0) {
			
			return status;
		}
		IStatus val= JavaConventions.validateJavaTypeName(sclassName);
		if (val.getSeverity() == IStatus.ERROR) {
			status.setError(NewWizardMessages.getString("NewTypeWizardPage.error.InvalidSuperClassName")); 
			return status;
		} 
		if (root != null) {
			try {		
				IType type= resolveSuperTypeName(root.getJavaProject(), sclassName);
				if (type == null) {
					status.setWarning(NewWizardMessages.getString("NewTypeWizardPage.warning.SuperClassNotExists")); 
					return status;
				} else {
					if (type.isInterface()) {