try
{
URL jurl = new URL( "jar:" + url.toString() + "!/" );
JarURLConnection connection =
(JarURLConnection) jurl.openConnection();
BlockManifest manifest =
new DefaultBlockManifest( connection.getManifest() );
final String group = manifest.getBlockGroup();
buffer.append( "\nBlock Group: " + group );
final File root = new File( m_base, group );
buffer.append( "\nLocal target: " + root );
JarFile jar = connection.getJarFile();