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 could return a copy of the data. The caller who chooses to change the data will only be changing the copy

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

    public String[] getArr() {

        String[] b = new String[arr.length];

        System.arraycopy(arr, 0, b, 0, arr.length);

        return b;
    }
}