All of the programs are Java files, and need to be run from a complete java environment. The easiest way is to import them into an IDE, such as Netbeans, IntelliJ IDEA, or any other competing IDE. Alternatively, the programs can be run from the command line after compiling them with the 'javac' command, followed by the 'java' command Note that for the CMD environment to function properly, both the java and javac commands should be in your PATH.