Ports are now available on all platforms (RFE 4782900).
MIDI device i/o is now available on all platforms (RFE's 4812168, 4782924).
Optimized direct audio access is implemented on all platforms (RFEs 4908240 and 4908879). It is enabled by default on systems which offer native mixing (i.e. Linux ALSA with hardware mixing, Solaris Mixer enabled, Windows DirectSound).
The new real-time Sequencer works with all MIDI devices and allows unlimited Transmitters (RFE 4773012).
The sound.properties configuration file allows choice of default devices (RFE 4776511). For details, see MidiSystem and AudioSystem for details.
MidiDevices can query connected Receivers and Transmitters (RFE 4931387, methods MidiDevice.getReceiver and MidiDevice.getTransmitter).
AudioFormat, AudioFileFormat, and MidiFileFormat now have properties that allow further description and qualification of the format (RFEs 4925767 and 4666845).
A set of ease-of-use methods allow easier retrieval of lines from AudioSystem (RFE 4896221).
The Sequencer interface is extended with loop methods, for seamless looping of specific portions of a MIDI sequence (RFE 4204105).
Java Sound no longer prevents the VM from exiting (bug 4735740).
Refer to the documentation at http://java.sun.com/j2se/1.5.0/docs/guide/sound/index.html.