Where to find Liberty documentation

WebSphere® Liberty is built on the open source Open Liberty codebase and many Liberty capabilities and features are now documented on the Open Liberty website. However, capabilities that are specific to WebSphere Liberty and some heritage features and capabilities are documented only in the WebSphere Liberty documentation.

To align with open source principles of transparency and community participation, Open Liberty documentation is maintained in an open source GitHub repository and hosted on the open source Open Liberty website. Under the stewardship of the Open Liberty documentation team, the Java development community is free to contribute to this documentation. Community participation makes the documentation more robust, promotes a culture of knowledge sharing, and encourages a more diverse pool of contributors.

If you are developing cloud-native applications to run on either Open Liberty or WebSphere Liberty, you can probably find everything that you need in the Open Liberty docs, guides, and blog. However, for applications that require WebSphere Liberty-specific capabilities or licensing configuration, you can find information about topics like installation, running WebSphere Liberty in a container, and migrating from WebSphere Application Server to Liberty in IBM Docs.

Liberty feature documentation

Liberty features are modular units of function that enable the runtime capabilities your application needs. Reference information for all Liberty features and configuration elements is available in both WebSphere Liberty and Open Liberty documentation. However, many Open Liberty feature pages also include configuration examples that are not available in the WebSphere Liberty documentation.

Many Liberty features that were developed before the initial Open Liberty release are documented throughout the WebSphere Liberty documentation. A small subset of Liberty features is available only in WebSphere Liberty and these features are not documented in Open Liberty.

For example, multiple versions of the RESTful Web Services feature (formerly JAX-RS) are documented in both WebSphere Liberty and Open Liberty. However, the versions that are documented and the extent of the information that is included is different in each documentation set:

The original version of the feature, jaxrs-1.1, is available only in WebSphere Liberty and is documented only in the WebSphere Liberty documentation.
Reference information for subsequent versions of the feature, such as restfulWS-3.1, appears in both documentation sets, but the the Open Liberty feature page for restfulWS-3.1 includes reference material and configuration examples that aren't included in the WebSphere Liberty feature page for restfulWS-3.1.

For more information about which features are available in each Liberty edition and Open Liberty, see Liberty features.

Liberty documentation in IBM Docs

The Liberty documentation in IBM Docs covers a wide range of runtime features and capabilities, particularly those capabilities that are associated with monolithic applications that run on virtual machines (VMs). This documentation includes technology and practices that go back to the debut of Liberty in 2012. While some of this information might be less relevant to modern cloud-native applications, it supports applications that are modernizing or that use features and capabilities that are specific to WebSphere Liberty.

Rather than duplicating Liberty open source documentation in IBM Docs, relevant topics provide links to the latest Liberty documentation on the Open Liberty website. These links are annotated with the easily recognizable Open Liberty icon: .

A subset of Liberty capabilities is available and supported only in the WebSphere Liberty runtime. Documentation for these capabilities is available exclusively in the WebSphere Liberty documentation.

The WebSphere Liberty documentation also includes WebSphere Liberty-specific information about licensing for container workloads and how to use the WebSphere Liberty operator to deploy and manage these workloads. For more information, see Running WebSphere Liberty in a container section.

The WebSphere Liberty documentation includes reference information for all Liberty features, configuration elements, and Liberty API and SPI documentation.

The WebSphere Liberty documentation is updated with each Liberty version, though most new development is documented exclusively on the Open Liberty website. In cases where the most current information about a topic is documented in Open Liberty, links are provided in the WebSphere Liberty topic to the corresponding Open Liberty topic. You can find information about the updates in each release on the What is new in this release of Liberty page.

Documentation for WebSphere Liberty on z/OS operating systems

Open Liberty is not supported on z/OS® operating systems. All documentation that is specific to using Liberty on z/OS, including the small set of z/OS-only Libertyfeatures, is available only in the WebSphere Liberty documentation. However, features and capabilities that apply generally to various editions of Liberty, including z/OS, are documented in both WebSphere Liberty and Open Liberty, according to the previously described conditions. In the Open Liberty documentation, general information that includes operating system-specific code, such as command line or directory structure examples, is presented in Linux format. In the Open Liberty guides, steps that are operating system specific are presented in Windows, MAC, and Linux format.

For example, the z/OS-only z/OS SAF Integration 1.0 feature (zosSecurity-1.0) is documented only in the WebSphere Liberty documentation. However, the JSON Web Token Single Sign-On 1.0 feature (jwtSso-1.0) is available in all Liberty editions. This feature is documented in both WebSphere Liberty and Open Liberty, though the Open Liberty jwtSso-1.0 feature page includes configuration examples that aren't included on the WebSphere Liberty jwtSso-1.0 feature page.

Documentation for WebSphere Liberty on IBM i operating systems

Open Liberty is not supported on IBM i operating systems and all documentation that is specific to using Liberty on IBM i is available only in the WebSphere Liberty documentation. However, information that applies generally to various supported operating systems for Liberty, including IBM i, is documented in both WebSphere Liberty and Open Liberty, according to the previously described conditions. In the Open Liberty documentation, general information that includes operating system-specific code, such as command line or directory structure examples, is presented in Linux format. In the Open Liberty guides, steps that are operating system specific are presented in Windows, MAC, and Linux format. In the WebSphere Liberty documentation, the IBM i icon indicates information that is specific to IBM i operating systems.

Liberty documentation on the Open Liberty website

The Open Liberty website provides the information that you need to develop, deploy, and manage cloud-native applications, regardless of whether you are running an Open Liberty or WebSphere Liberty instance. Except for WebSphere Liberty-specific capabilities and features, all new Liberty runtime development is documented on the Open Liberty website, which is updated for each Liberty release version.

Liberty documentation on the Open Liberty website is provided in three different formats, according to the type of information:

Docs

The Open Liberty Docs cover cloud-native application development, deployment, operations, security, and more. The docs include conceptual, task-based, and reference information on the full range of open source Liberty runtime features and capabilities. The feature reference pages also include a collection of concise configuration examples for many Liberty features to help you quickly configure your runtime to support the capabilities that your applications need.

By default, the information in Open Liberty Docs applies to the most recent four-week release of the runtime. However, you can view documentation for earlier versions. Select your chosen version from the menu at the beginning of the Open Liberty Docs navigation. When you select an earlier version of the documentation, it includes only the features, settings, and capabilities that are valid for that particular version.

Guides

The

Open Liberty Guides are a collection of self-contained, hands-on tutorials that both explain and demonstrate different Liberty runtime capabilities. Each guide shows how to build a simple application that demonstrates a particular aspect of Liberty development and explains how the code works as you go. Open Liberty guides cover such topics as

Getting started, Open Liberty

securing an application, Open Liberty

providing metrics, Open Liberty

documenting APIs, and many more. New guides are regularly added to help you quickly and confidently learn to use Liberty capabilities.

Blog posts

The Open Liberty Blog provides posts from the Open Liberty developer community on all kinds of topics, from in-depth analysis of development practices to the latest community news. It also includes the GA and beta release posts, which detail all the new features and enhancements in each release.