The spec says, for InvocationContext.getMethod():

getMethod

java.lang.reflect.Method getMethod()

Returns the method of the target class for which the interceptor was invoked. For method interceptors, the method of the target class is returned. For lifecycle callback interceptors, a null value is returned.

Returns:
the method, or a null value

However, currently invoking InvocationContext.getMethod() in a interceptor's lifecycle callback method returns a non-null value.