This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
Right. So the problem isn't with Java, it's with your use of the command line. First you should set out to discover what command will create a new window. A simple web search led me to this handy reference. Once you have the command, you'll still need a command interpreter to run it, so your exec line should include a call to it. Let us know what you try and if you are still stumped.