Marcin is enthusiast of clean coding and good design. He is the author of "Mockito Instant" and "Mockito Cookbook" books and co-author of the Groovy @Builder and "micro-infra-spring" microservices open source solution. He has contributed to open several source projects (including Groovy, Mockito, Spring-Cloud-Zookeeper, Spring-Cloud-Sleuth, Rest-assured, Drools, Moco). Also Marcin is the author of Uptodate Gradle plugin and Spock subjects-collaborators extension open source projects and co-founder of the Warsaw Groovy User Group. Furthermore, he is a member of the Most Valuable Blogger program at DZone and Java Code Geeks.