How to Open Up a JAR File

1. Open a Web browser, navigate to Java.com and download a free copy of Java. Click on the red 'Free Java Download' button to initiate the download. Save the downloaded file to your desktop.

2. Double-click the Java download on your desktop and follow the on-screen prompts to install Java on your computer.

3. Locate the JAR file that you want to open – it will have a '.jar' extension at the end of the file name.

4. Double-click on the JAR file. If the file contains a compressed Java program, it will open and run automatically. Otherwise, continue on to the next step.

5. Right-click on the JAR file and select 'Open' from the context menu. The archived files within will be unpacked. JAR files sometimes contain a collection of several different Java programs. In this case, you can also use a ZIP file compression utility such as WinZip to open the JAR file.