Java is a programming language that allows programmers to design high-performance, dependable programs. Because Java is a platform-independent language, programmers can write code that runs on a wide range of hardware and software platforms. A module in an application is a self-contained component that is segregated from other components and can be utilized in various applications. You must first compile a Java module into an a.jar file before running it. After that, you can run the.jar file with the java command. Individual classes in the.jar file can also be executed using the java command. Similarly, the javac command can be used to build Java modules and classes.