Preventing composition problems in modular java applications

Abstract

Java JAR files have become a common means to bring reusability into Java programming. While they allow developers to easily share and use third-party libraries, they bring new challenges as well. This paper addresses the problem of Linkage Errors that occur when a type incompatibility or a missing dependency between two libraries is detected at runtime. This is a direct impact of composing applications from pre-existing binary libraries as the problem would be normally detected during compilation. A problem may occur relatively easily as rules of source and binary compatibility in Java differ and may be counter-intuitive. To deal with this problem, we offer a set of tools that analyse existing binaries and discover problems normally leading to runtime errors. The tools work automatically, may complement existing testing, and find problems effectively from the start of development. Their additional features such as detection of redundant or duplicated libraries are usually not provided by standard testing tools.