ConGu is a tool that supports the checking of Java classes against property-driven algebraic specifications. Checking classes consists in determining, at run-time, whether the classes that are subject to analysis behave as required by the specification. The first version of the tool, available here, reduce the problem to the run-time monitoring of contract annotated classes, which is supported today by several runtime assertion-checking tools. In ConGu 2.0, which is also applicable to generic datatypes implemented by generic Java classes, the run-time monitoring of the implementations is achieved through bytecode instrumentantion and use of assertions. ConGu 2.0 is available in the QUEST plug-in for the Eclipse IDE.