Migrate JAX-RPC to JAX-WS for Liberty: Automated conversion guide

Modernizing Java applications to run on WebSphere Liberty offers significant benefits, such as modular architecture, cloud readiness, and improved performance. However, for many organizations, one challenge has consistently slowed or prevented this journey: legacy applications built with JAX-RPC. JAX-RPC APIs are not available in recent versions of enterprise Java; to modernize, the recommended approach is migrating application code to use JAX-WS APIs. The JAX-RPC to JAX-WS Source Migration Helper (which is available in AMA Dev Tools) can help to do this in your IDE.

What are JAX-RPC and JAX-WS?

JAX-RPC (Java API for XML-Based RPC) is a legacy Java EE technology that enables web services by using remote procedure calls over XML. It was widely used in older applications to allow distributed systems to communicate. In 2006, however, as part of Java EE 5, JAX-WS was introduced as a replacement for JAX-RPC, and JAX-RPC was then deprecated in 2009 with the release of Java EE 6. Although JAX-RPC is supported by the WebSphere Application Server traditional runtime, it is not supported on most modern Java runtimes, including Liberty.

JAX-WS (Java API for XML-Based Web Services) is the modern standard for SOAP-based web services in Java, and the official successor to JAX-RPC. JAX-WS replaces the deprecated JAX-RPC API while maintaining compatibility with existing WSDL contracts and service endpoints. It supports newer protocols and standards, allows simpler annotation-based configuration, and is fully supported on Liberty and other modern Java runtimes.

Historically, the only way to be able to migrate an application from JAX-RPC to JAX-WS was a very manual process of analyzing the code then modifying it, including updating service interfaces and configuration files, refactoring Java source code to use JAX-WS annotations instead of JAX-RPC patterns, and more. For large applications, this could require hundreds of developer hours, taking significant time away from being able to implement innovative features and improvements. Traditionally, modernizing JAX-RPC applications was one of the biggest barriers to running an older application on a modern application runtime. However, thanks to the new JAX-RPC to JAX-WS Source Migration Helper, this process can now be automated.

Automating conversion with the JAX-RPC to JAX-WS Source Migration Helper

The JAX-RPC to JAX-WS Source Migration Helper scans your applications to identify where JAX-RPC is used, then guides you step-by-step through converting your applications from using JAX-RPC to using JAX-WS. The migration helper can make the source code changes for you, reducing the manual effort required to modernize the application.

While the migration helper aims to automate as much as possible with deterministic outcomes, certain changes still require manual intervention. When manual code changes are needed, the migration helper identifies and guides you through reviewing the changes and making the required manual updates to complete the migration.

The JAX-RPC to JAX-WS Source Migration Helper is available as part of IBM Application Modernization Accelerator Developer Tools (AMA Dev Tools), an IDE plugin that helps you quickly and easily modernize your enterprise Java applications.

How to migrate JAX-RPC to JAX-WS using AMA Dev Tools

When planning a migration that includes converting JAX-RPC to JAX-WS, you must complete the JAX-RPC modernization work before any other modernization changes. This is because later versions of Java EE do not necessarily include the JAX-RPC APIs, which the migration helper needs in order to advise and provide fixes.

With AMA Dev Tools installed in your IDE, right-click an application’s project, then click Modernize Java Applications > Modernize to Liberty:

You are then prompted to build and analyze the application according to the target application server and Java version that you want the application to run on.

When AMA analyzes the application, if JAX-RPC is detected in your application, you are automatically prompted to use the JAX-RPC to JAX-WS Source Migration Helper.

The migration helper scans your application to find all web service definitions (WSDL files), and assesses them for migration readiness. It provides a report that identifies which services are ready for migration, which are unsupported, and which are unused by your application. For each eligible migration candidate, the helper guides you through the process, one WSDL file at a time. It runs automated code updates first to address the majority of changes, before guiding you through any necessary manual updates, as shown in the following example:

The migration helper then asks you to review the files that were created by running the automated code updates. When you have finished reviewing, making the required changes, and ensuring your application compiles, you can mark this WSDL file complete, then move on to the next one.

When you’ve finished this process for each WSDL file, you can build and analyze the application, and then continue your application modernization.

For more information, see Migrating JAX-RPC services to JAX-WS services in the Application Modernization Accelerator (AMA) documentation.

Summary

The JAX-RPC to JAX-WS Source Migration Helper lowers the biggest barrier to modernization: JAX-RPC technology. As part of the AMA Dev Tools, the migration helper makes it much easier to modernize your applications to run on Liberty, all from within your IDE.

Next steps

The JAX-RPC to JAX-WS Source Migration Helper is available in AMA Dev Tools for Visual Studio Code and AMA Dev Tools for Eclipse IDE.

AMA Dev Tools is part of the JSphere Suite for Java portfolio and requires a valid access key. Customers using IBM Enterprise Application Runtimes (EAR) and IBM Modernized Runtime Extension for Java (MoRE) can obtain a key to start using the AMA Dev Tools.

You can download the plug-ins directly from your IDE marketplace:

• AMA Dev Tools for Visual Studio Code
• AMA Dev Tools for Eclipse IDE