How to Start an Executable JAR
Usually the .jar file extension is associated with the Java runtime. That means that just by double-clicking an executable JAR the application should start. Unfortunately executable JARs have the same extension as other JARs, such as libraries. So you can't tell which JAR is executable, unless you look at its MANIFEST.MF file.
On the command line, you start an executable JAR by running java with the -jar option:
C:\Users\tim\tmp>java -jar jarfiller-example.jar

