code: public static String getPackageName(Object obj)
  	{
  		if(obj == null)
  			throw new NullPointerException("obj is null");
  		return getPackageName(obj.getClass());
  	}
docs: Get the package name for a object.
  @param obj The object to get the package name for.
  @return the object's class's pacakge name.
  @throws NullPointerException if obj is null.