try { // Create a URL that refers to a jar file on the net URL url = new URL("jar:http://hostname/my.jar!/"); // Create a URL that refers to a jar file in the file system url = new URL("jar:file:/c:/almanac/my.jar!/"); // Get the jar file JarURLConnection conn = (JarURLConnection)url.openConnection(); JarFile jarfile = conn.getJarFile(); // When no entry is specified on the URL, the entry name is null String entryName = conn.getEntryName(); // null // Create a URL that refers to an entry in the jar file url = new URL("jar:file:/c:/almanac/my.jar!/com/mycompany/MyClass.class"); // Get the jar file conn = (JarURLConnection)url.openConnection(); jarfile = conn.getJarFile(); // Get the entry name; it should be the same as specified on URL entryName = conn.getEntryName(); // Get the jar entry JarEntry jarEntry = conn.getJarEntry(); } catch (MalformedURLException e) { } catch (IOException e) { }