Android basically OS which is used for mobile device and we can call as android platform also.
Initially developed by Andy rubin and their team and later acquired by google. Now android OS varied by version and feature too.
1.Gingerbread(2.3) 2.Honeycomb(3.0) 3.Ice Cream Sandwich(4.0) 4.Jelly Bean(4.3/4.2/4.1) 5.KitKat(4.4) 6.Lollipop(5.0) 7.Marshmallow(6.0) 8.Nougat(7.0) 9.Oreo(8.0)
Each Android OS version different from one another
DVM 1.virtual machine 2.ART supports a number of new debugging options, particularly in monitor- and garbage collection-related functionality. For example, you can: 3.In Dalvik vitual machine ,we can able to See what kind of locks are held in stack traces, then jump to the thread that holds a lock. 4.Mostly , we can ask how many live instances here present are of a given class, ask to see the instances, and see what references are keeping an object live. Filter events (like breakpoint) for a specific instance. 5.The value returned by a method when it using method event exit triggering here. 6.Set field watchpoint to suspend the execution of a program when a specific field is accessed and/or modified. 6.Dalvik vitual machine is Register based which is designed to run on low memory also, uses its own byte code and runs .Dex file 7.Finally we are getting .apk file