just clone the source from GitHub and import it to java IDE example; Eclipse, IntelliJ, Netbeans. to run just click the run button.
https://www.wikihow.com/Run-Java-Program-in-Eclipse for eclipse
you can also use command prompt without installing some IDE but make sure your device already installed java
open a command prompt window and go to the directory where you saved the java program (MyFirstJavaProgram.java). Assume it's C:.
Type 'javac MyFirstJavaProgram.java' and press enter to compile your code. If there are no errors in your code, the command prompt will take you to the next line (Assumption: The path variable is set).
Now, type ' java MyFirstJavaProgram ' to run your program.
You will be able to see the result printed on the window.