Peter Welkenbach works as a consultant, senior architect, and trainer in the fields of requirement engineering, object-oriented methodologies, software engineering, and quality management. He has more than 20 years experience of designing and implementing complex information systems for banks, automotive manufacturers, and pharmaceutical companies. For 10 years he has been a technology evangelist for Java technology and the use of the corresponding frameworks in customer projects. Peter Welkenbach is a course developer, author of numerous publications, and speaker at JAX and international Oracle conferences. He has been using Spring in numerous customer projects since it first appeared in summer 2003. His current focus is on enterprise architecture and lean architecture methodologies. In his current projects he works as an enterprise architect for a well known German retailer.