In the domain of Software Engineering, program analysis and understanding has been considered to be a very challenging task since decade, as it demands dedicated time and efforts. The analysis of source code may occasionally be comparatively easier due to its static nature, however, the back end code (Bytecode), especially in terms of Java programming, is complicated to be analysed. In this paper, we present a methodological approach towards understanding the Bytecode of Java programs. We put forward a framework for the debugging process of Java Bytecode. Furthermore, we discuss the debugging process of Bytecode understanding from simple to multiple statements with regards to data flow analysis. Finally, we present a comparative analysis of Bytecode along with the simulation of the proposed framework for the debugging process