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

You must return a copy of your array.

public String[] getArr() {
  return arr == null ? null : Arrays.copyOf(arr, arr.length);
}