12. How final keyword works in java ?

Answer:

Given to

• Classes
• Methods
• Variables
• Inner classes.

Notes:

• A final modifier makes the value of a primitive as a constant, with an object reference variable the reference variable makes it as constant. This means you can't re-assign the same reference variable to point another object.
• A final variable must be initialized at the time of declaration.
• If a class is declared as final then all the methods inside the class are implicitly final. So the final methods may not be overrided.
• The class cannot be subclassed if defined as final class, this avoids the inheritance.

13. How java abstract modifier behaves?

Answer
Given to

Classes
Methods

• An abstract class can't be instantiated i.e. you may not make a new call on it. In an ordinary class, if one method is declared as abstract, then the class must be declared as abstract.
• The abstract class contains only method signatures without body of the method, the body lies in the subclass. (A subclass must provide the implementation).
• The same thing applies, when you implement an interface, it insists to provide method implementation.

14. Explain About 'native' Modifier?

Answer:
Given to
Methods.
Native methods are used in Java programs to load Non Java programs written C/C++ and etc..