Hi Guys,
Look at http://java.sun.com/j2se/1.4.2/docs/api/java/lang/Runtime.html#exec(java.lang.String)
However, I HIGHLY RECOMMEND AGAINST allowing users to specify parameters that determine what programs to run, or what parameters to pass the programs. You should be extremely careful that people don't include special characters, such as semicolons, that could cause them to execute arbitrary commands. The best way to guard against security attacks is to only allow specific argument IDs in your URLs, which are then translated into specific commands in Java.
Jon Emerson
http://www.jonemerson.net/