static void generateJarSerialVersionUIDs(URL jar, TreeMap classVersionMap,
ClassLoader cl, String pkgPrefix) throws IOException
{
String jarName = jar.getFile();
JarFile jf = new JarFile(jarName);
Enumeration entries = jf.entries();
while( entries.hasMoreElements() )
{
JarEntry entry = (JarEntry) entries.nextElement();
String name = entry.getName();
if( name.endsWith(".class") && name.startsWith(pkgPrefix) )