import java.net.JarURLConnection;
import java.net.URL;
import java.util.jar.JarFile;
public class Main {
public static void main(String[] argv) throws Exception {
URL url = new URL("jar:file:/c://my.jar!/");
JarURLConnection conn = (JarURLConnection) url.openConnection();
JarFile jarfile = conn.getJarFile();
}
}