How can I install .jar files on my Android? I downloaded some 3D games, unzipped them and got .jar files. How can I use these in Android?  I have a Galaxy S running 2.1.
Although Android uses java, it doesn't support normal JAR files. Instead it uses an Android specific format called APK. The main difference is that Android does not use the normal Java Virtual Machine, but contains it's own Dalvik Virtual Machine that's optimized for Android.