Want to play your favorite java based games (or any jar/jad application) on your new Android Phone? The Android app called Android J2ME MIDP Runner lets you right away port your existing J2ME [jar/jad] applications to Android package (apk) without source code.
To install Andorid J2ME MIDP Runner to your phone, download the app (andme-signed.apk) from here and run:
adb shell chmod 777 /data/dalvik-cache
adb install C:?<PATH TO YOUR DOWNLOADED andme.apk>?andme-signed.apk [Detailed information here]
The online solution for converting jar files to apk file is much simpler than the above method. Enter here and select an option to convert jar/jad files into android (apk) package. You can either give URL of a Jad file or upload the downloaded jar/jad file for conversion.