Bug 21631 JavaUI.createTypeDialog() should provide default message [dialogs]
2.0 Release If you use JavaUI.createTypeDialog() to create a new (single selection) type dialog, and then open the dialog, the open will fail silently. The dialog cannot be succesfully opened unless you send setMessage() to the dialog before you open it. This behaviour should be documented, or, preferably, a default message ("Please select a type/class/interface") should be provided.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/ui/JavaUI.java
public static IDocumentProvider getDocumentProvider() {
		return JavaPlugin.getDefault().getCompilationUnitDocumentProvider();
	}
	
	/**
	 * Sets the Javadoc location for an archive with the given path.
	 * 
	 * @param archivePath the path of the library; this can be an workspace path
	 * or an external path in case of an external library.
	 * @param url The Javadoc location to set. This location should contain index.html and
	 * a file 'package-list'.
	 * 
	 * @since 2.0
	 */
	public static void setLibraryJavadocLocation(IPath archivePath, URL url) {
		JavaDocLocations.setLibraryJavadocLocation(archivePath, url);
	}
	/**
	 * Returns the Javadoc location for an archive or <code>null</code> if no
	 * location is available.
	 * 
	 * @param archivePath the path of the library. This can be an workspace path
	 * or an external path in case of an external library.
	 * 
	 * @since 2.0
	 */	
	public static URL getLibraryJavadocLocation(IPath archivePath) {
		return JavaDocLocations.getLibraryJavadocLocation(archivePath);
	}
	/**