Elixir: An Automated Repair Tool for Java Programs

Object-oriented (OO) languages, by design, make heavy use of method invocations (MI). Unsurprisingly, a large fraction of OO-program bug patches also involves method invocations. However, current program repair techniques incorporate MIs in very limited ways, ostensibly to avoid searching the huge repair space that method invocations afford. To address this challenge, in previous work, we proposed a generate-and-validate repair technique which can effectively synthesize patches from a repair space rich in method invocation expressions, by using a machine-learned model to rank the space of concrete repairs. In this paper, we describe the tool Elixir that instantiates this technique for the repair of Java programs. We describe the architecture, user-interface, and salient features of Elixir, and specific use-cases it can be applied in. We also report on our efforts towards practical deployment of Elixir within our organization, including the initial results of a trial of Elixir on a project of interest to potential customers. A video demonstrating Elixir is available at: https://elixir-tool.github.io/demo-video.html.