The main topics of my thesis are application development and system integration on the Java EE platform. I have created three applications with different characteristics and these applications publish their business functions via traditional XML web services. I composed new services out of these in the integration space, in a higher abstraction layer. A lightweight user interface has also been created to present the working system. Functional testing was one of the key concepts in my work: I used testing best pracices and methodologies to ensure the robust operation of my applications services. During the development, the main target was creating a comparative analysis of the middleware products of the two giant vendors, putting a big emphasis on the ease of development and aspects of security, quality of service, service level agreement and management. For my work I used IBM's Websphere Application Server and Websphere
ESB and from the Oracle side I tested Weblogic Application Server and Oracle Service Bus.