code: public void setColor(Color color)
  	{
  		if (null == color)
  		{
  			String _message = "The color must be non null.";
  			Object[] _parameters = {};
  			throw new IllegalArgumentException(MessageFormat.format(_message, _parameters));
  		}
  		myColor = color;
  	}
docs: /*
  (non-Javadoc)
  
  @see com.sporniket.libre.ui.swing.paper.SheetOfPaper#setColor(java.awt.Color)