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Eclipse Transformer

Eclipse Transformer is an Eclipse Foundation project that provides tools and processes for transforming Java binaries and related artifacts so they can run on newer Jakarta and Java platform APIs.

  • Tooling for bytecode and archive transformation of Java applications and libraries (application modernization)
  • Support for updating Java EE–based artifacts to Jakarta EE namespace usage (Java platform and Jakarta EE migration)
  • Command-line and automation-friendly utilities for bulk transformation of JARs and other archives (build and Continuous Integration and Continuous Deployment (CI/CD) integration)
  • Configurable transformation rules that operate on class files, manifests, and other packaging metadata (build tooling)
  • Eclipse-hosted open-source project under the Eclipse Technology top-level project (open-source governance)

More About Eclipse Transformer

Eclipse Transformer is an open-source project under the Eclipse Foundation that focuses on automated transformation of Java application binaries so they align with updated platform APIs, especially the Jakarta EE namespace changes introduced after the transition from Java EE to Jakarta EE. It addresses the problem that many existing Java EE applications and libraries are compiled against older javax.* namespaces and related APIs, which are not compatible with newer jakarta.* APIs used in current Jakarta EE runtimes.

The project provides tooling for bytecode-level transformation (application modernization) that operates directly on compiled class files and packaged archives such as JARs, WARs, and EARs. Instead of requiring access to original source code, Eclipse Transformer works on binary artifacts, rewriting package and class references where appropriate to conform to the Jakarta EE namespace model and other supported transformation rules. This enables organizations to reuse existing builds while targeting newer platform runtimes.

Eclipse Transformer includes utilities that can be invoked from the command line or scripted within build pipelines (build and CI/CD integration). These tools are designed to be used in automated processes, for example as part of Continuous Integration (CI) workflows that take legacy Java EE artifacts, apply transformation rules, and produce updated binaries suitable for deployment on Jakarta EE–compatible application servers. Configuration files and rule sets control how transformations are applied, giving teams the ability to tailor behavior to specific application structures or dependency sets.

The project operates within the broader Java and Jakarta ecosystem (Java platform tooling), supporting enterprises that maintain existing Java EE workloads while planning migration to Jakarta EE environments. By focusing on namespace and binary-compatible transformations, Eclipse Transformer reduces the need for manual refactoring of large codebases when source code is incomplete, unavailable, or costly to modify. It serves as a complement to source-level migration tools and documentation by covering the binary and packaging layer of modernization efforts.

From an enterprise architecture perspective, Eclipse Transformer fits in the category of application modernization and migration tooling (modernization tooling). It is relevant for platform engineers, application owners, and middleware teams who need to standardize runtimes on Jakarta EE while continuing to use existing Java artifacts. As an Eclipse Foundation project, it follows the foundation’s governance, licensing, and community processes, which supports integration into enterprise open-source adoption policies and dependency management workflows.