Dynamic Refactoring-aware Automated Update of Java Online Applications

Refactorings of software components (e.g., libraries and frameworks) can change the APIs of the components. To use the latest version of a component, applications that reuse those APIs need to be updated. Traditionally, this is done manually, which is error-prone, tedious, and disruptive. The problem is exacerbated for long-running applications (e.g., servers) that cannot be shut down, updated, and restarted. This paper presents a practical approach and our tool, dReAM, to automat-ically and safely update running Java applications without restarting them. At the core lies a formal representation of programs to validate the composition of refactorings and other API changes to both component and application. If dReAM finds that there are no conflicts between components and API changes, then the running application can be safely transformed to work with the new API. To apply these API changes at runtime, dReAM extends JikesRVM, a popular JVM. Case studies on Jigsaw web server and James mail server show