How shall we write get method, so that private fields don't escape their intended scope? [duplicate]

Answer 1

class SafeStates {

  private List<String> states;

  public List<String> getStates() {
    return states;
  }

  public void setStates(List<String> states) {
    this.states = Collections.unmodifiableList(states);
  }
}

Answer 2

You can use Java's Arrays and Collections. to create a read only wrapper.

return Collections.unmodifiableList(Arrays.asList(states));

NOTE: don't worry about the Strings getting modified, they're immutable.