The appropriate testing of applications is an important task in software development. Nowadays object oriented programming languages are not capable to indicate every type of errors, so it is necessary to develop new methods with which the testing can be carried out more efficiently. In my master thesis I review what advantages the extended finite state machine modell has over the Java Virtual Machine. I show a possible method for describing the model as a graph. To exploit the advantages of a finite state machine in programming, a special software is needed that is capable to transform the object orientated programming language to a model of a finite state automaton effectively. In my master thesis I show how a source code written in Java can be transformed into a finite state machine model and then how it can be represented graphically. My application executes the above-mentioned conversion and it represents the model as a graph. My application is also able to simulate the functional running of these graphs and it saves the obtained results in logging files. I review the functioning of my application (transformation of Java source codes to extended finite state machines, running the model and the testing of it) through examples of use and I also show the structure of my program.