Jarfix is a free tool that helps recapture .jar association with the Java Runtime Environment. If your PC does not run your Java files when opening items with the .jar extension, then you may need to re-associate them properly.
What use is Jarfix?
Since .jar is such a common file extension, there are multiple programs that can hijack the extension and result in .jar files being opened by the wrong program when run. Jarfix helps rescue your .jar files and re-associate them with the JRE (Java Runtime Environment) so that you can run your Java files as expected when opening them. It's a simple, lightweight program that comes in at under 1MB and can be run as an .exe as any other executable on Windows. This will solve the problem and re-associate the file extension. There are also some optional parameters you can use when running the program, which add features like opening the help file, running without dialogue, running with elevated permissions and fixing association for one user profile or the entire PC at once.
Simple extension fix
Jarfix is useful for Java developers and others who frequently want to run .jar files but find that other programs are hijacking the extension. It is a lightweight, easy to use and completely free program.