public synchronized void setData(byte[] buf, int offset, int length)
public void setData(byte[] buf)
  public synchronized void setData(byte[] buf, int offset, int length)  {		// This form of setData must be used if offset is to be changed.		if (buf == null)			throw new NullPointerException("Null buffer");		if (offset < 0)			throw new IllegalArgumentException("Invalid offset: " + offset);		buffer = buf;		this.offset = offset;    setLength(length);	}