Bug 51895 Error when recovering javadoc archive path for a jar
1. add swt.jar to the Java build path of a project 2. open the properties dialog for this jar from the package explorer 3. change the javadoc location to : [x] javadoc in archive archive path: <path_to_eclipse>/plugins/org.eclipse.platform/doc/isv/doc.zip (in my case '/home/luc/host/eclipse/plugins/org.eclipse.platform/doc/isv/doc.zip') path within archive: reference/api 4. close the properties dialog 5. reopen the properties dialog The leading slash is missing, the dialog display the error 'the archive is missing '
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/JavadocConfigurationBlock.java
*
	 * @param message the error message
	 */
	protected void displayErrorDialog(String message) {
		MessageDialog.openError(fShell, ERROR_DIALOG_TITLE, message); 
	}
		
	private String chooseJavaDocFolder() {
		String initPath= ""; 
		if (fURLResult != null && "file".equals(fURLResult.getProtocol())) { 
			initPath= (new File(fURLResult.getFile())).getPath();
		}
		DirectoryDialog dialog= new DirectoryDialog(fShell);
		dialog.setText(PreferencesMessages.getString("JavadocConfigurationBlock.javadocFolderDialog.label")); 
		dialog.setMessage(PreferencesMessages.getString("JavadocConfigurationBlock.javadocFolderDialog.message")); 
		dialog.setFilterPath(initPath);
		String result= dialog.open();
		if (result != null) {
			try {
				URL url= new File(result).toURL();
				return url.toExternalForm();
			} catch (MalformedURLException e) {
				JavaPlugin.log(e);
			}
		}
		return null;
	}
		
	private IStatus updateURLStatus() {
		StatusInfo status= new StatusInfo();