Peer-to-peer networks consist of thousands or millions of nodes that might join and leave arbitrarily. The evaluation of new protocols in real environments is many times practically impossible, especially at design and testing stages. The purpose of this paper is to describe the implementation aspects of a new Java based P2P simulator that has been developed to support scalability in the evaluation of such P2P dynamic environments. Evolving the functionality presented by previous solutions, we provide a friendly graphical user interface through which the high-level theoretic researcher/designer of a P2P system can easily construct an overlay with the desirable number of nodes and evaluate its operations using a number of key distributions. Furthermore, the simulator has built-in ability to produce statistics about the distributed structure. Emphasis was given to the parametrical configuration of the simulator. As a result the developed tool can be utilized in the simulation and evaluation procedures of a variety of different protocols, with only few changes in the Java code.