This major report describes the design and implementation of the TROM-SRMS: software reliability measurement system for real-time reactive system in the TROMLAB environment. The TROM-SRMS is responsible for the reliability computation of each individual sub-system in a real-time reactive system. In order to achieve cross-platform capability, Java has been chosen as the implementation tool. A GUI interface is added on top of the real computation unit to facilitate the use of the software. Finally, the key algorithms used in the design and implementations are presented in detail as well as the interactions among the underlying objects.