Consider the following class: 

public class Sequence

{

private ArrayList values;

public Sequence() { values = new ArrayList(); }

public void add(int n) { values.add(n); }

public String toString() { return values.toString(); }

}

Add a method public Sequence append (Sequence other) that creates a new sequence, appending this and the other sequence, without modifying either sequence. For example, if a is 1 4 9 16 and b is the sequence 9 7 4 9 11 then the call a.append (b) returns the sequence 1 4 9 16 9 7 4 9 11 without modifying a or b.