This document discusses declarative input validation using JSR 303 and ExtVal. It begins with an introduction of the speaker, Bart Kummel, and his experience. It then discusses how validation code is often duplicated in classic Java EE applications. JSR 303 and ExtVal aim to remove this duplication by allowing validation to be defined through annotations. The document demonstrates several examples of validation annotations and ExtVal features like cross-validation and customization. It emphasizes that ExtVal provides benefits for both Java EE 5 and 6 by enabling annotation-based validation and additional advanced options.