Java Question Notes

1. final class A {}; //  Define a final class:
- Cannot be subclass. (String is a final class)
- The methods in the class are also final => run twice faster than normal method!
-Extends: abstract class b{}: an abstract class with can have methods
                interface class b{}:

2.   volatile int b;  // an indicator to Thread that do not cache value of this variable

3.