This paper presents a novel, high performance and low cost execution architecture for the system level GALS programming language SystemJ, which extends Java with synchronous reactive features present in Esterel and asynchronous constructs of CSP (Communicating Sequential Processes). The new architecture is based on JOP (Java Optimized Processor), which is a hardware implementation of the Java Virtual Machine (JVM). The JOP, inherently suited to data-driven transformational operations, is extended to efficiently execute the control constructs and control flow of SystemJ. The new core, which is called RJOP (Reactive JOP) supports efficient execution of both data dominated and control dominated embedded applications. It also maintains the time-predictable execution of the applications intended for real-time embedded systems and calculation of Worst Case Reaction Time (WCRT) as provided by the original core. The initial results indicate significant performance improvement and lower resource requirements over the existing architectures used for the SystemJ execution.