Running Java Applications


The Java files on this site are all as Jar files. The Jar file contains all the components such as class file and graphics that make up the application.

One of the advantages of Java is that the applications here should happily run on Windows, Mac and Linux (and others) as long as Java is installed. This page will give instructions and pointers on how to find and install Java.


There are two acronyms you may come across when looking to install Java:

Installing a Java Runtime

Most Java JRE / JDK's are based on OpenJDK which is the free and open source implementation of Java. OpenJDK is contributed to by Oracle and many other companies and individuals. Because of this open nature of Java, many companies such as Microsoft and Amazon provide Java distributions too.

As I use the Java distribution created by Adoptium (who refer to their Java distribution as Eclipse Temurin), that will be the one I will describe the download and install process for. The other distributions have similar steps.

When you have finished, you should be able to run Java Jar files by double clicking on them!

Bonus Tip

To find out the version of Java you have installed (if any), on the command line, type java -version e.g.:

>java -version
openjdk version "11.0.19" 2023-04-18
OpenJDK Runtime Environment Temurin-11.0.19+7 (build 11.0.19+7)
OpenJDK Client VM Temurin-11.0.19+7 (build 11.0.19+7, mixed mode)

If you have the JDK installed, or to see if it is installed, at the command line, type javac -version e.g.:

>javac -version
javac 11.0.19