code: private static Class<?> boxTypeFor(Class<?> primType) {
  		if (primType == int.class) {
  			return Integer.class;
  		}
  		else if (primType == boolean.class) {
  			return Boolean.class;
  		}
  		else if (primType == byte.class) {
  			return Byte.class;
  		}
  		else if (primType == char.class) {
  			return Character.class;
  		}
  		else if (primType == double.class) {
  			return Double.class;
  		}
  		else if (primType == float.class) {
  			return Float.class;
  		}
  		else if (primType == long.class) {
  			return Long.class;
  		}
  		else if (primType == short.class) {
  			return Short.class;
  		}
  		throw new IllegalStateException("Forgotten a case in this method?");
  	}
docs: What's the "boxed" version of a given primtive type.