Design by contract (DbC) is a software development methodology that focuses on clearly defining the interfaces between components to produce better quality object-oriented software. Though there exists ample support for DbC for sequential programs, applying DbC to concurrent programs presents several challenges. Using Java as the target programming language, we tackle such challenges by augmenting the Java Modelling Language (JML) and modifying the JML compiler (jmlc) to generate runtime assertion checking code to support DbC in concurrent programs. We applied our solution in a carefully designed case study on a highly concurrent industrial software system from the telecommunications domain to assess the effectiveness of contracts as test oracles in detecting and diagnosing functional faults in concurrent software. Based on these results, clear and objective requirements are defined for contracts to be effective test oracles for concurrent programs whilst balancing the effort to design them. Effort is measured indirectly through the contract complexity measure (CCM), a measure we define. Main results include that contracts of a realistic level of completeness and complexity can detect around 76 percent of faults and reduce the diagnosis effort for such faults tenfold. We, therefore, show that DbC can be applied to concurrent software and can be a valuable tool to improve the economics of software engineering.

The idea behind Design by Contract (DbC) is that a method defines a contract stating the requirements a client needs to fulfill to use it, the precondition, and the properties it ensures after its execution, the post condition. Though there exists ample support for DbC for sequential programs, applying DbC to concurrent programs presents several challenges. We have proposed a solution to these challenges in the context of Java as programming language and the Java Modeling language as specification language. This paper presents our findings when applying our DbC technique on an industrial case study to evaluate the ability of contract-based, runtime assertion checking code at detecting and diagnosing race conditions and deadlocks during system testing. The case study is a highly concurrent industrial system from the telecommunications domain, with actual faults. It is the first work to systematically investigate the impact of contract assertions for the detection of race conditions and deadlocks, along with functional properties, in an industrial system.

Though there exists ample support for Design by Contract (DbC) for sequential programs, applying DbC to concurrent programs presents several challenges. In previous work, we extended the Java Modeling Language (JML) with constructs to specify concurrent contracts for Java programs. We present a runtime assertion checker (RAC) for the expanded JML capable of verifying assertions for concurrent Java programs. We systematically evaluate the validity of system testing results obtained via runtime assertion checking using actual concurrent and functional faults on a highly concurrent industrial system from the telecommunications domain.

Design by contract (DbC) is a software development methodology that makes use of assertions to produce better quality object-oriented software. The idea behind DbC is that a method defines a contract stating the requirements a client needs to fulfill to use it, the precondition, and the properties it ensures after its execution, the postcondition. Though there exists ample support for DbC for sequential programs, applying DbC to concurrent programs presents several challenges. The first challenge is interference, the product of multiple threads of execution modifying and accessing shared data. The second is the specification of thread-safety properties in the presence of inheritance.We present a solution to these challenges in the context of Java programs by extending the Java modeling language (JML) specification language. We experiment our solution on a large size industrial software system.