What Java external packages/libraries out there?

I need to know what are the most helpful, easy-to-use packages out there for developing games in Java?

I need packages for:

• Network/Online
• Sound/Music
• 2D graphics (I'm not interested in 3开发者_Go百科D)
• Database

You mentioned you're not interested in 3D, but you ought to take a look at LWJGL. It handles access to OpenGL (which you can create a 2D renderer with), OpenAL (sound/music) and controllers (gamepads, etc).

For the Physics you can use:

http://www.jbox2d.org/

is a port from the C physics engine box2d