What is a java virtual machine???

Answer 1

http://stackoverflow.com/questions/7674839/is-the-jvm-a-compiler-or-an-interpreter

Answer 2

In simple terms, It is what makes the language cross-platform, it is what makes the app work on any device, browser, phone, tv etc. Write once use everywhere

Answer 3

kind of software which translate your code according to the platform.

so, your app can be used everywhere