Question

My query is, can a getter method ever return a wrapper data type? Will it violate the principle of Encapsulation? Why not? Is immutability of classes a part of encapsulation?

public class TestGetter{
private Integer a;
public TestGetter(int _a){
    a = _a;
}
public Integer getA(){
   return a;
      }
 }

In Some client code:

TestGetter tg  = new TestGetter(5);
Integer corruptX = tg.getA();//This should return the reference
corruptX = null;

So now
a = null?

When i run it i dont see a as null.

Answer 1

This is no different to:

Object a = new Object();
Object b = a;
b = null;
// a is not null here

Modifying a reference is not the same as modifying the object being referred to.

To answer your question about encapsulation; yes, it’s ok to return a reference to an Integer member variable, because Integer instances are immutable.