Manifold F.A.Q.s - Frequently Asked Questions (and Answers)

Common QuestionsGetting HelpTroubleshooting

Common Questions

Q: Does Manifold support Java 11? 15? 8?

Yes. Manifold fully supports Java 8 - 17. Manifold also fully supports the Java Platform Module System (JPMS). See the Setup Guide for more info.

Q: Manifold is somehow using Java internal APIs to do its magic. Could it break in a future version of Java?

Unlikely. Java internal APIs can and do change from version to version, sometimes dramatically, however Manifold always adjusts to changes ahead of Java releases. To date, Manifold has adapted to eight major Java versions since its debut, always well in advance of Oracle’s official release schedule.

Q: Is Manifold free?

Yes, the Manifold project is open source and publicly available on github, free for use via Apache License 2.0.

Q: Does Manifold work with Maven? Gradle?

Yes. Please refer to the Setup instructions.

Q: Does Manifold provide IDE support?

Yes. The Manifold plugin provides comprehensive support for IntelliJ IDEA and Android Studio.

Download / Update the plugin directly from within the IDE:

SettingsPluginsMarketplace ➜ search: Manifold

Note: The IDE notifies you within 24 hours when an update is available and gives you the opportunity to sync.

Q: Do I really need a license for the IntelliJ plugin?

The IntelliJ plugin is offered separately via the JetBrains Marketplace. It is free for use with IntelliJ IDEA Community Edition after a 30 day free trial. Similarly, it is free for use with IntelliJ IDEA Ultimate Edition after a 30 day free trial, however after the trial the plugin lightly nags about the trial expiration, but you can continue to use it if you don’t want to purchase the license.

Q: How do I get manifold-fill-in-blank working with my project?

Add the manifold-fill-in-blank dependency[s] to your project along with the -Xplugin:Manifold javac argument, the setup is sensitive to the version of Java you are using, generally whether you are using Java 8 or 9+. See the Setup docs for complete instructions.

Getting Help

Q: Where can I find help?

Discussions Join our Slack Group to start a discussion, ask questions, provide feedback, etc.

Report A Bug The Manifold project uses github issues to track bugs, features, and other requests. If you discover a bug, have a feature request, or an idea go here and let it be known. Expect a response within 24 hours.

Private E-mail If your question or issue is more pressing or confidential, don’t hesitate to send an email to

Q: I’ve read the docs page. Can I learn more about Manifold elsewhere?

Links to recently published Manifold articles are available on the Articles page. There is always another article on the way, check back for more.


Q: I updated to the latest Manifold IntelliJ plugin and now IntelliJ is complaining with error messages. What’s wrong?

You probably need to update your project dependencies to use the latest manifold release. If your project’s dependencies are out of sync, the plugin tells you which version of manifold you need with in a warning message when you load your project. You can find the latest releases here.

Important: If you are using Maven or Gradle, you must update your build files – do not change the Module dependencies from IntelliJ’s UI. Please refer to the Maven and Gradle sections of the Manifold Setup instructions.

Please make some noise if you can’t get it working, chances are you’re not alone and help will arrive soon.

Q: I defined some useful extension methods, but they aren’t showing up in my other project. How can I share them as a dependency?

The module with your extension methods must declare that it should be processed for extension methods. Do that with the Contains-Sources JAR manifest entry. For instance, from Maven:

      <!--class files as source must be available for extension method classes-->

Please see the documentation for making extension libraries.

Q: I defined a new extension class with some extension methods, IntelliJ flags usage of them as errors. What’s wrong?

Sometimes IntelliJ’s cache is out of sync with extensions. The simplest remedy is to refresh the project from source control using the Refresh (🗘) tool command:

scm refresh