Guaranteeing response times of real-time (RT) distributed computing systems has been recognized as one of the biggest challenges by the RT software research community for three decades. The concept of a hybrid approach that combines analytical derivation approaches and testing-based statistical derivation approaches in a symbiotic form for meeting this challenge was presented in recent years. However, concrete practical hybrid approaches are still in early stages of development. One such approach pursued by the authors and their collaborators is presented here. This paper focuses on the cases of deriving tight execution time bounds of the segments of object methods which do not involve calls for services from the operating system kernel and middleware. A case-study that demonstrates how the adopted approach works in handling a simple practical application is also presented.