After an earlier change of software developing paradigms, the communication between several heterogeneous systems is implemented by following the service-oriented architecture. SOA is an architectural pattern in which application components provide services to other components via a communications protocol, typically over a computer network. The concrete implementation of the SOA architecture is the web service. Upon introduction, the popular web services were the ones based on SOAP and WSDL, nowadays the lightweight REST architecture is also used in a wide area of software systems. In this document, we get to know these 2 types of web services, the differences between the two, and we use them in a university research project in order to solve a given problem. I will introduce the project itself, after we make acquaintance with how the web services evolved, how they work, after that I implement the two web services based on the JAX-WS and JAX-RS Java libraries, I make clients for these servers, test them, compare them, document them, and at the end, I will evaluate the results, and make a summary.