1. Simply Download The java emulating platform app from this link .
2. Then extract the content to your pc because it is in Zip format. Open the folder and run Kemulator.exe .
3. Then download the java games / application (.jar) you want to play to your system.
4. navigate to midlet then to Load jar or Load, then locate and select the game /application you will like to play from the list of games / application you have downloaded or already have in your computer .
5. Enjoy your java games / app with pc experience .
Source : how to run / play Java Games/application On your Computer