My name is Jonas Bergström and I live in Stockholm, Sweden. I program for a living, my current employer is in the internet gaming industry. Previously I've worked in the telecom and finance sectors.
C4J came about when I realized that the Design By Contract framework I've written for my employer (using Java's dynamic proxies) could be significantly improved using Java 5's javaagent option and byte code instrumentation. When I looked around for other DBC libraries for Java and realized that none existed that follows basic object orientation principles, I decided to implement one myself - and C4J was born.