Unified Modeling Language is a general purpose modelling language used in the field of software development to easily visualize the systems by specifying the static and dynamic aspects of the system. The conventional way of implementing design models is by writing programs in high level languages like java by a programmer. Our method automatically generates platform independent executable code in the form of bytecode without a programmer and it can be executed on any platform. The design models comprising of class and activity diagrams after parsing and syntax verification are converted to an autobytecode model. The autobytecode model is further processed to determine the execution sequence comprising of loops, sequential and conditional statements. The execution sequence, the actions and attributes associated with the nodes in the execution sequence are analyzed to automatically generate complete bytecode directly from the autobytecode model created from design models.