What environment variables do I need to set up before I start running Java programs on my machine?

Before running Java programs on your machine you need to set two environment variables namely,

• PATH − The path environment variable is used to specify the set of directories which contains execution programs.
• When you try to execute a program from command line, the operating system searches for the specified program in the current directly, if available, executes it.
• In case the programs are not available in the current directory, operating system verifies in the set of directories specified in the ‘PATH’ environment variable.
• CLASSPATH − The classpath environment variable is used to specify the location of the classes and packages.
• When we try to import classes and packages other than those that are available with Java Standard Library.
• JVM verifies the current direction for them, if not available it verifies the set of directories specified in the ‘CLASSPATH’ environment variable