OpenJML

OpenJML is a static analysis tool for Java that allows developers to check the correctness of their Java code against formal specifications written in the Java Modeling Language (JML). JML is a specification language that extends Java with constructs for describing the intended behavior of Java code, including preconditions, postconditions, invariants, and ghost variables. OpenJML uses these specifications to verify properties of the Java code, such as ensuring that methods adhere to their stated contracts.

The tool can perform several types of analysis. Runtime assertion checking involves instrumenting the Java code to check JML specifications during execution, which helps catch violations as they occur. Static checking, on the other hand, attempts to prove properties of the code without executing it, often by translating the Java code and JML specifications into a format that can be analyzed by a theorem prover. OpenJML supports various theorem provers, such as ESC/Java2, KeY, and the Z3 SMT solver, to aid in this static verification process.

OpenJML is developed as an open-source project and is part of the larger OpenJML project, which aims to provide a comprehensive suite of tools for formal software development in Java. It is used by researchers and practitioners interested in improving the reliability and correctness of Java software through formal methods. The tool can be integrated into development workflows and build systems to automate the verification process.