As the roles of Java in business and e-business applications continue to grow, all iSeries and AS/400 IT professionals have a choice to make—learn Java or get left behind. Programmers, development managers, and architects who want to stay on the cutting edge of their careers must learn how to use and understand Java. IBM is not abandoning RPG, but more and more Java is finding a role in leading-edge applications. For an RPG programmer, learning Java can be daunting, but with the right help, it's a skill that can be mastered. This completely revised and updated edition offers that help by gently yet comprehensively teaching the Java language and core Java-supplied functionality.