• What is the Toolbox?
• Changes in Version 20 and Newer
• Download/Installation
  • Maven
  • Download Information
• Migration to GitHub
• Support information

JTOpen is the open source software product known as the "IBM Toolbox for Java." It is also commonly referred to "jt400" or simply "the toolbox." In short, this package provides a set of Java classes that enable applications to integrate with IBM i

JTOpen is governed by the IBM Public License.

JTOpen is the open source counterpart to a version of the IBM Toolbox for Java that is delivered as part of the 5770-SS1 Licensed Program Product (LPP). The LPP version is supported by IBM and can be obtained from the IBM Toolbox for Java web site. The Toolbox is available as an installable licensed program for IBM i. Here is a breakdown of the supported Toolbox releases versus operating system versions:

There are several key changes introduced into JTOpen starting with version 20.x. These differences warranted a significant version jump to differentiate from 11.x and earlier code streams. Key differences include:

1. Adoption of semantic versioning, based on the guidelines published at semver.org. In summary, JTOpen versions now consist of three digits, x.y.z. This provides differentiation between bug fixes, new features, and breaking changes.

2. Java 7 or later is required (breaking change).

3. Function signatures may be changed from previous versions, in an effort to add typesafety. Version 20 will remain source-compatible, but may have binary incompatibility (breaking change).

4. Breaking changes may be introduced on major version upgrades. Some examples of breaking changes include:

   • Newer minimum Java version requirements
   • Changes in Java classes that require source modification or recompilation
   • Dropped support for older releases of IBM i Note that Version 20 contains some breaking changes as documented here.

5. Changes to code hosting location and support processes (see Migration to GitHub and Support information)

6. Immediate removal of several antiquated components of JTOpen, including

   • JTOpenLite
   • jt400Android
   • jt400Micro
   • jt400Proxy
   • jt400Servlet

   If you need these packages, please acquire older versions from the archive site on sourceforge (breaking change)

7. Publication of "native" form to Maven Central (see Download Information). This allows Maven-based applications running on IBM i to take advantage of extra optimizations present in the operating system

The recommended way to build Java applications is to use Maven, Gradle, or some other system to manage dependencies. Manually maintaining a Java classpath is not desired.

JTOpen is published to Maven Central as artifact ID jt400 in group net.sf.jt400. Visit specific versions on the jtopen page on Maven Central for example build declarations for Maven's pom.xml manifest file. Configuration text is also available for other build systems, including Gradle, SBT, Ivy, Grape, Leiningen, and Buildr.

Several coordinates are published to Maven. See Download Information for information about Maven coordinates

JTOpen releases for versions 20 and newer include the following files:

As of April 2023, the JTOpen site on sourceforge.net is considered a historical archive for older versions. GitHub is now used for issue tracking, release management, etc.

Please note the following regarding support/collaboration options:

• Documentation for JTOpen can be found on the Toolbox web site.
• See the "Community" section of the IBM i open source resources page for community forums/chat/etc. In particular, the Ryver forums have a topic dedicated to Java development and is a good place to discuss JTOpen.
• The JTOpen mailing list has been discontinued
• You may submit a GitHub issue for bug reports, enhancement requests, or questions.
• In general, the version of toolbox shipped with the IBM i operating system is supported by IBM as part of a software maintenance agreement ("SWMA")