In earlier versions of Windows & by default, JAR files were opened & run by the current Java installation. Somewhere along the way however, this file association can be broken. For example, WinRAR (a popular compression/extraction utility) may be defaulted to open the JAR files as compressed archives - allowing one to view the contained files but providing no means by which to run them. Also, later versions of Windows (currently, such as Windows 10) simply do not have JAR files associated with the current Java installation for whatever reason. So, users upgrading to 10 may suddenly find such programs are no longer loading. Yet, rest assured! The program likely still works! ...It just needs a little help loading.
Now certainly, the JAR file still needs Java to run. Yet if a user does not happen to know either the command-line syntax or where the necessary files are, this already poses a bit of a problem - especially since the folder in which Java is located is not always the same but often times reflects the specific version of that particular Java installation. Luckily, Java's folder is most often added automatically to the default system path, and this helps us find where it is. Even if one knows how to do all this, it can be a bit of a hassle to do each time one wishes to load a JAR application.
JAR_Runner locates the current Java installation, calls the appropriate application (JavaW.exe), & directs it to run the JAR file. It integrates right into the Windows system & also has a CMD/DOS command line option.
Click-and-drag JAR file onto the JAR_Runner EXEcutable or shortcut
Right-click JAR file, select "Open with", navigate to JAR_Runner EXEcutable (Of course, one can make this the default for JAR files from now on)
Command line syntax: JAR_RUNNER [drive:][path]filename