3. Provide an example of how to achieve encapsulation in Java. 
4. Is it possible to declare abstract methods as private? 
a. Justify your answer. 
5. Is it compulsory for a class, which has been declared as abstract, to have at least one abstract method?

class which contains the abstract keyword in its declaration is known as abstract class. But, if a class has at least one abstract method, then the class must be declared abstract. 

(Object Oriented Programming in c++)

3. Provide an example of how to achieve encapsulation in Java.

Answer the following short questions. Your answer should be precise.

1. Can we declare base class constructor or destructor as virtual if yes then why we want to do?
2. How we can declare a class as abstract and why we need abstract classes?
3. Why we cannot able to create objects of abstract classes give reasonable justification of that.   

This question is related to Object orientated programming in c++