A modification of Java virtual machine for counting bytecode commands

The objective of the thesis was to implement or modify an existing Java virtual machine (JVM) in a way that it will allow insight into statistics of the executed Java instructions of an executed user program. The functionality will allow analysis of the algorithms in Java environment. After studying the theory of Java and Java virtual machine, we decided to modify an existing Java virtual machine. We chose JamVM which is a lightweight, open-source Java virtual machine under GNU license. The idea was divided into minimal modification of JamVM and implementation of own Java library. The Java library will, within the user application program, allow access to information and statistics of executed Java instructions. At the end, we have implemented and presented a simple use of our solution.