Experience on Automatically Converting a C++ Monolith to Java EE

TL;DR

This paper shares the experience and techniques of converting a large C++ monolith into Java EE, including architecture changes, handling language differences, and developing a tool for continuous Java code regeneration.

Contribution

It introduces a practical approach and tools for converting a massive C++ codebase into Java EE, addressing common language and architectural challenges.

Findings

Successful Java EE deployment on WildFly

Effective handling of C++ features in Java conversion

Development of a clang-tool-based regeneration process

Abstract

Converting a large C++ code base (800k lines of code) into Java alone is challenging. Changing the architecture from a monolith into an application adhering to the Java application server standard and to run it on WildFly is a different number. This report describes the experience made during the C++ to Java conversion, the techniques used as well as the way to success of running the Java code on the application server for the first time. The approaches to solve the usual C++ to Java culprits, like multiple inheritance, enum-handling and scoped objects are described. A clang-tool-based software is developed to continuously regenerate the Java, because development on the C++ code base continued.