How do you specify a port range for Java sockets?

Binding the socket to any free port is (usually) a feature of the operating system's socket support; it's not specific to java. Solaris, for example, supports adjusting the ephemeral port range through the ndd command. But only root can adjust the range, and it affects the entire system, not just your program.

If the regular ephemeral binding behavior doesn't suit your needs, you'll probably have to write your own using Socket.bind().