J-LO A tool for runtime-checking temporal assertions

We present a Runtime Verification framework for Java programs called the Java Logical Observer, J-LO for short. Properties can be specified in Linear-time Temporal Logic (LTL) over AspectJ pointcuts. These properties are checked during program-execution by an automaton-based approach where transitions are triggered through aspects. No Java source code is necessary since AspectJ works on the bytecode level, thus even allowing instrumentation of third-party applications. As an example, we discuss safety properties and lock-order reversal. A novelty of our approach is that we provide a special form of LTL allowing free variables in propositions which can bind objects on the execution trace.