How do I prevent the modification of a private field in a class?

Question

Imagine that I have this class:

public class Test
{
  private String[] arr = new String[]{\"1\",\"2\"};    

  public String[] getArr() 
  {
    return arr;
         


        

Answer 1

The nub of the problem is that you are returning a pointer to a mutable object. Oops. Either you render the object immutable (the unmodifiable list solution) or you return a copy of the object.

As a general matter, finality of objects does not protect objects from being changed if they are mutable. These two problems are "kissing cousins."