a set of core libraries that provides most of the functionality available in the core libraries
of the Java programming language.
Every Android application runs in its own process, with its own instance of the Dalvik
virtual machine. Dalvik has been written so that a device can run multiple VMs efficiently.
The Dalvik VM executes files in the Dalvik Executable (.dex) format which is optimized for
minimal memory footprint. The VM is register-based, and runs classes compiled by a Java
language compiler that have been transformed into the .dex format by the included ―dx‖
Android only supports applications written using the Java programming language at this