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 Sequence a is

1 4 9 16

and b is

9 7 4 9 11

then the call a.append(b) will return the sequence

1 4 9 16 9 7 4 9 11

leaving both a and b unchanged.