Android runs on Java amongst other things.
Android's use of Java is special in several ways. The Android API differs greatly from other standard Java J2SE and J2ME APIs. Secondly, the use of the Dalvik VM means that Android packages cannot just be run under desktop operating systems such as Linux, Windows, or Mac OSX. This may seem counter-intuitive because Android is built on Linux. The difference between the Android OS and the Linux OS is significant and not easily fixed.
Android malware is on the rise. There are two reverse-engineering articles under Malware.