Add guide on adding custom Java function library#543
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This guide / use case is based on a question and subsequent solution provided in the public mailing list: https://lists.evolveum.com/pipermail/midpoint/2026-January/008670.html
licehammer
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Apr 7, 2026
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You can expect the person reading this is a java programmer.
| :page-description: Package Java classes to JAR files to use them as custom functions in midPoint expression scripts | ||
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| MidPoint makes compiled Java classes available to all script expressions similarly to functions in expression function libraries. | ||
| Methods of public classes packaged in JAR files and placed in midPoint home directory are accessible in expressions using their fully qualified class name. |
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Technically it can be placed anywhere on classpath (which includes MIDPOINT_HOME/lib). You can then address using fully qualified class name or use java import mechanism.
| Requirements and constraints: | ||
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| * Classes must be `public`. | ||
| * Methods called from expression scripts must be `public static`. |
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It should work even with non-static methods, but you would have to instantiate the class first which is an overkill for most scripts.
| * Classes must be `public`. | ||
| * Methods called from expression scripts must be `public static`. | ||
| * The class and its dependencies must be compatible with the JVM version midPoint runs on. | ||
| * Do not use package or class names that would collide with those already used by midPoint. |
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You can use colliding class names. That's why Java have packages.
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This guide / use case is based on a question and subsequent solution provided in the public mailing list: https://lists.evolveum.com/pipermail/midpoint/2026-January/008670.html
I humbly ask for a fact-check / review of the article from someone on the eng (or dev) team. Thank you.