Software transactional memory (STM) programs usually use more memory resources than traditional programs. Therefore, estimating an upper bound of memory resources used by an STM program is crucial for optimizing the program and reducing the risks of out-of-memory runtime exceptions. However, due to the complex nesting of transactions and threads, the estimation problem is challenging. In our previous work, we have developed several type systems to address the problem for core imperative languages with STM primitives. This work advances our previous works, in which we add object-oriented constructs to the language while keeping the STM primitives, to make the language closer to practical languages. Then, we built a type system to statically estimate the maximum memory required by well-typed programs of the language.

This paper proposes a transformation-based method to automatically generate functional test cases from use cases named USLTG (Use case Specification Language (USL)-based Test Generation). We first focus on developing a modeling language named Test Case Specification Language (TCSL) in order to express test cases. Test cases in TCSL can contain detailed information including test steps, test objects within steps, actions of test objects, and test data. Such information is often ignored in currently available test case specifications. We then aim to generate test cases in a TCSL model by a transformation from use cases that are represented by a USL. The USLTG transformation includes three main steps in generating (1) scenarios, (2) test data, and (3) a TCSL model. Within our transformation, the OCL solver is employed in order to build system snapshots as the part of test cases and to identify other test data. We applied our method to two case studies and evaluated our method by comparing it with other recent works.

Class models are often employed to represent domains. In order for class models to conform to their intended domain semantics, we need to ensure their precision and consistency. Precision can be achieved by augmenting the models with constraints, and consistency can be achieved by avoiding contradictory constraints. Model finding is a technique to maintain this kind of consistency. It automatically checks the satisfiability of models by using example instances. However, this technique is often inefficient when applied to large models due to the huge search space. In this paper, we propose a technique to narrow the search space by using patterns to represent constraints. Constraint patterns allow us to put further restrictions on the search space. Our case study illustrates that using constraint patterns in this way can improve the verification process.

In this paper, we present an approach to find upper bounds of heap space for Java Card applets. Our method first transforms an input bytecode stream into a control flow graph (CFG), and then collapses cycles of the CFG to produce a directed acyclic graph (DAG). Based on the DAG, we propose a linear-time algorithm to solve the problem of finding the single-source largest path in it. We also have implemented a prototype tool, tested it on several sample applications, and then compared the bounds found by our tool with the actual heap bounds of the programs. The experiment shows that our tool returns good estimation of heap bounds, runs fast, and has a small memory footprint.

We propose an approach based on aspect-oriented programming to specify and to verify interaction protocols in the component interfaces of Java programs. First, based on method patterns of AspectJ we introduce a simple protocol specification language that specifies temporal orders of operations of an interface. We then develop an algorithm that takes a protocol specification and produces aspect code that will check for protocol conformance of programs that use the interface at runtime. Finally, we propose several extensions that enable the integration of our approach with static techniques and allow checking protocols over multiple components.