Install Java

Java Virtual Machine (JVM) is the part of the Java software platform that executes Java code. It is a program which executes certain other programs, namely those containing Java bytecode instructions. To compile Java code, you need to have some version of JVM installed.

Java is most likely preinstalled on your computer, unless you are using Mac OS X 10.8 (Mountain Lion).

Mac install instructions

Open a Terminal window (click on Applications -> Utilities -> Terminal from the dock). Then type "java -version" at the prompt. If it return with something like "java version "1.6.0_35"", then Java is already installed and you don't have to do anything else. Otherwise, it should pop up a window to install Java. Click the "Install" button to install Java.