OVal is a generic validation framework for any kind of Java objects (not only JavaBeans) and allows you:

to specify constraints for class fields and method return values

to easily validate objects on demand

to specify constraints for constructor parameters that are automatically checked when the constructor is called

to specify constraints for method parameters that are automatically checked when the method is called

to enforce full object validation after an object instance has been created

to enforce full object validation before a method of the object is called

to enforce full object validation after a method of the object is called

to either let OVal throw constraint violation exceptions during automatic checks or alternatively notify constraint violation listeners.

to easily create custom constraints