To check which version of Java you have on your Windows computer, you'll need to open the Command Prompt.

You can check which Java version is on your Mac to see if you have the most up-to-date Java running, or you can check on the Java website.

To do the same, open Command Prompt and then run the following command to check which version of Java is installed on your computer.

The next time you need to examine command line arguments and things get a little complex, whip out your trusty open source Java toolkit, and use Command Line Interface (CLI).