public class XMAS
{
    public XMAS (boolean debug)
    {
        _debug = debug;
    }

    private boolean _debug;
}
import java.util.*;

public class XMAS
{
    public XMAS (boolean debug)
    {
        _debug = debug;
    }

    public Vector<Integer> validate (Vector<Integer> input, int preamble)
    {
        Vector<Integer> invalid = new Vector<Integer>();
        int index = 0;

        return invalid;
    }

    private boolean _debug;
}
Update XMAS.java