You should have these two environmental variables to allow Java to function correctly:
JAVA_HOME: C:\ (YOUR_JDK_LOCATION) \bin
Path: (The same as JAVA_HOME)
For example, my environmental variables would appear like this:
JAVA_HOME: C:\Program Files\Java\jdk1.7.0_05\bin
Path: C:\Program Files\Java\jdk1.7.0_05\bin
You do not need to set the EV named "Classpath"; Java will function fine without it. As a suggestion though, compiling through the command line is fairly old-hat and may cause you a lot of stress if you run in to a mistake with your code you have no idea how to fix. You really want to be trying out some Java IDEs (Integrated Development Environments), such as Netbeans (available from Oracle's website) or Eclipse.
Last edited by Jemdt; 06-25-2012 at 08:07 PM..