With Web services, distributed applications can be encapsulated as self-contained, discoverable software components that can be integrated to create other applications. BPEL allows for the composition of existing Web services to create new higher-function Web services. We identified that the techniques currently applied at development time are not sufficient for ensuring the reliability of composite Web services In this paper, we present a language-based approach to transparently adapting BPEL processes to improve reliability. This approach addresses reliability at the Business process layer (i.e the language layer) using a code generator, which weaves fault-tolerant code to the original code and an external proxy. The generated code uses standard BPEL constructs, and therefore, does not require any changes to the BPEL engine.
