import java.util.*;

public class Memory
{
    public Memory ()
    {
        _memory = new Vector<Long>();
    }

    private Vector<Long> _memory;
}
import java.util.*;

public class Memory
{
    public Memory ()
    {
        _memory = new Vector<MemoryElement>();
    }

    private Vector<MemoryElement> _memory;
}
Update Memory.java