I've been trying to create a Minecraft server from CraftBukkit the past few hours. I know I need Java, so I tried downloading it. When I went to the command prompt and typed in "java-version", it kept coming up with the same thing. "not recognized as an internal or external command, operable program or batch file." So I uninstalled it, and tried redoing it, and same thing. There was a few times when Java itself wouldn't install. So I looked at youtube videos, forums, and I kept seeing things about changing the Path/classpath in environmental settings. I tried everything multiple people were saying, and I did it exactly the way they said, and it kept saying the same thing. Why won't my computer recognize Java, even after I set the path?

I'm using a Windows 7 64-bit system.