We present the Tester, a 100% Java benchmarking tool designed to accept a custom representation of a load schedule and reproduce it using distributed client machines in order to test a service. Our implementation is strongly based on a set of interfaces and pluggable implementations allowing for custom extensions. This project was realized at the Conrad Zuse Institut in Berlin, in a CoreGrid Research Exchange Program. One of the features of our application is the addition of the ZIB's Sminer Project Preferences library, a hierarchical data structure extracted from an XML configuration file, allowing for multiple customisation possibilities.