EMF Validation Builder is an Eclipse plugin that automates the validation process at the time of saving. This means that resource problem markers are up to date as soon as you save your model. A dependency table is maintained, which allows the validation process to be re-run when necessary. In particular, the tool can be directly used with ECore model files.
Serene is a validation engine that implements the JAXP 1.3 Validation Framework API for RELAX NG based on an algorithm centered on providing good messages and having a clear handling of ambiguity and conflicts. It has an implementation of the JAXP Validation Framework API for ISO Schematron and support for Schematron markup embedded in RELAX NG schemas.
Android Saripaar is a simple, yet powerful rule-based UI validation library for Android. It following features declarative style validation powered by Annotations, synchronous and asynchronous validations (you don't have to worry about threading), compatibility with Stock Android Widgets, custom view dependencies, quick setup (just download the jar and include it in your libs project folder), removal of most of your validation logic from your code, and compatibility with other annotation frameworks such as AndroidAnnotations, RoboGuice, etc.,