Approaches to runtime checking have to track the execution of a software system and therefore have to deal with generating and processing execution events. Often these techniques are applied at the code level - either by inserting new source code prior to the compilation or by modifying the target e.g. Java byte code, before running the program. The jassda framework and tool enable runtime checking of Java programs against a CSP-like specification.For generating events it uses the Java Debug Interface (JDI) and thus no modifications to the code are necessary. Another advantage is that events are generated on demand, i.e. dynamically at runtime it is determined which events to generate for the current debug run without modifying the program itself. This paper shows how this event generation is done by the jassda framework.