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Overview
As organizations modernize their Java workloads, many are moving from traditional WebSphere Application Server (tWAS) to WebSphere Liberty for its lightweight, modular, and cloud-ready architecture.
A common challenge during this migration involves applications built using JAX‑RPC–based web services. This blog outlines the key considerations, differences in support, and required actions for a successful transition.
Why Upgrade JAX‑RPC Applications?
JAX‑RPC (Java API for XML-based RPC) is a legacy web services specification that has reached end of life:
Deprecated in Java EE 6
Removed in Java EE 7
WebSphere Liberty aligns with modern Java EE / Jakarta EE standards and therefore:
JAX‑RPC is not supported in WebSphere Liberty
Impact
Applications using JAX‑RPC cannot be deployed on Liberty without modification. These applications must be upgraded to JAX‑WS before migration.
Differences: Traditional WebSphere vs WebSphere Liberty (Web Services)
Traditional WebSphere Application Server
Supports JAX‑WS
Provides backward compatibility for JAX‑RPC
Suitable for legacy workloads
WebSphere Liberty / Open Liberty
Supports JAX‑WS and Jakarta XML Web Services
Does not support JAX‑RPC
Designed for modern, cloud-native applications
Is JAX‑RPC Supported in WebSphere Liberty?
No, JAX‑RPC is not supported in WebSphere Liberty.
Version History
WAS 8.5.5.x (Java EE 6): JAX‑RPC deprecated
WAS 9.0.5.x (Java EE 7): JAX‑RPC removed
WebSphere Liberty: JAX‑RPC not available
Required Action
All JAX‑RPC–based web services must be migrated to JAX‑WS prior to deployment on Liberty.
Enabling JAX‑WS in WebSphere Liberty
To enable JAX‑WS support, configure the appropriate feature in the server.xml file.
Example: Enable JAX‑WS
<featureManager>
<feature>jaxws-2.2</feature>
</featureManager>
Example: Enable Full Java EE 7 Stack
<feature>javaee-7.0</feature>
Key Differences Between JAX‑RPC and JAX‑WS
Aspect
JAX‑RPC
JAX‑WS
Specification
JSR 101
JSR 224
Java Version
Java 1.4+
Java 5+
Annotations
Not supported
Fully supported
SOAP Support
SOAP 1.1 only
SOAP 1.1 and 1.2
Data Binding
Custom serializers
JAXB 2.0
Asynchronous
Supported
MTOM/XOP
WS-Addressing
Migration Tools
IBM provides tools to assist in upgrading JAX‑RPC applications to JAX‑WS.
JAX‑RPC to JAX‑WS Source Migration Helper
Available through AMA Dev Tools:
Visual Studio Code
IntelliJ IDEA
Eclipse IDE
Capabilities
Identifies deprecated APIs
Assists with source code transformation
Accelerates modernization
Access Requirements
AMA Dev Tools are part of the JSphere Suite for Java portfolio and require a valid access key.
Customers using:
IBM Enterprise Application Runtimes (EAR)
Modernized Runtime Extension for Java (MoRE)
can obtain access to these tools.
Download AMA Dev Tools
VS Code: https://ibm.biz/~pQzD3Qc2c
IntelliJ: https://ibm.biz/~XTltM6Iae
Eclipse: https://ibm.biz/~peQSwC06h
Summary
When migrating to WebSphere Liberty:
JAX‑RPC is not supported and must be replaced
Upgrade to JAX‑WS is mandatory
Enable required features (jaxws-2.2 or javaee-7.0) in server.xml
Use IBM AMA Dev Tools to streamline migration
Conclusion
Migration to WebSphere Liberty provides an opportunity to modernize legacy web services and align with current industry standards. By upgrading from JAX‑RPC to JAX‑WS, organizations can ensure compatibility, improve maintainability, and prepare their applications for cloud-native environments.
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