To do the same, open Command Prompt and then run the following command to check which version of Java is installed on your computer.

The "open" program is specific to OS X and lets you basically drag and drop a file with the -a command onto an application. This way it overrides the per-user OBJ open-with settings.

Create, view, and modify Java archive files on the command line Learn how to do basic CRUD operations on JAR, WAR, and EAR files using the command line.