public synchronized void setData(byte[] buf) {   if (buf == null) throw new NullPointerException("Null buffer");  buffer = buf;
public void setData(byte[] buf) { setData(buf, 0, buf.length);
	public synchronized void setData(byte[] buf) {		// This form of setData requires setLength to be called separately		// and subsequently.		if (buf == null)			throw new NullPointerException("Null buffer");		buffer = buf;	}