Bug 6672 jar no longer exported after attach source
1206 1. Create a project test. 2. Add a jar (say resources.jar) to the classpath and export the entry 3. Attach source (say resourcessrc.zip) to the jar. Notice, the jar is no longer exported - this information is discarded during the attach source process.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/wizards/buildpaths/SourceAttachmentBlock.java
* Opens a dialog to choose a root in the file system.
	 */	
	private URL chooseJavaDocLocation() {
		String initPath= ""; 
		if (fJavaDocLocation != null && "file".equals(fJavaDocLocation.getProtocol())) { 
			initPath= (new File(fJavaDocLocation.getFile())).getPath();
		}
		DirectoryDialog dialog= new DirectoryDialog(getShell());
		dialog.setText(NewWizardMessages.getString("SourceAttachmentBlock.jdocdialog.text")); 
		dialog.setMessage(NewWizardMessages.getString("SourceAttachmentBlock.jdocdialog.message")); 
		dialog.setFilterPath(initPath);
		String res= dialog.open();
		if (res != null) {
			try {
				return (new File(res)).toURL();
			} catch (MalformedURLException e) {
				
				JavaPlugin.log(e);
			}
		}
		return null;		
		
	}
		
	private Shell getShell() {
		if (fSWTWidget != null) {
			return fSWTWidget.getShell();
		}
		return JavaPlugin.getActiveWorkbenchShell();			
	}