How to Resolve IntelliJ Not Recognizing JavaFX 11 with OpenJDK 11

How can I fix IntelliJ IDEA not recognizing JavaFX 11 packages when using OpenJDK 11?

If IntelliJ IDEA is unable to recognize JavaFX 11 with OpenJDK 11, there are various configuration settings and dependencies you should check. This common issue can usually be resolved through a few key adjustments in your project settings or dependencies.

// Example VM options configuration
--module-path C:\path\to\javafx-sdk-11\lib --add-modules javafx.controls,javafx.fxml

Causes

• The JavaFX library is not correctly added to the project dependencies.
• Project SDK is not properly configured to use OpenJDK 11.
• Incorrect module settings that do not include the JavaFX library.
• Missing runtime arguments for JavaFX modules.

Solutions

• Ensure that you have added the correct JavaFX dependencies to your `pom.xml` or build.gradle file, depending on whether you are using Maven or Gradle.
• Check that the project is using the correct SDK version (OpenJDK 11). Go to `File -> Project Structure -> Project` and confirm the SDK settings.
• Add the JavaFX libraries to your module dependencies. Navigate to `File -> Project Structure -> Modules`, select your module, and add the JavaFX libraries under the 'Dependencies' tab.
• If using Maven, make sure to include the correct JavaFX modules as follows:
• <dependency> <groupId>org.openjfx</groupId> <artifactId>javafx-base</artifactId> <version>11.0.2</version> </dependency> <dependency> <groupId>org.openjfx</groupId> <artifactId>javafx-controls</artifactId> <version>11.0.2</version> </dependency> <dependency> <groupId>org.openjfx</groupId> <artifactId>javafx-fxml</artifactId> <version>11.0.2</version> </dependency>
• Set the VM options to include the JavaFX modules when running your application. You can do this by specifying the following in the VM options: `--module-path path oxuildolder --add-modules javafx.controls,javafx.fxml`.

Mistake: JavaFX libraries are not added to the project's dependencies properly.

Solution: Make sure you include all necessary JavaFX modules in your build configuration.

Mistake: Using an incorrect or outdated JavaFX version.

Solution: Ensure that the version of JavaFX matches the OpenJDK version you're using.

Mistake: Not configuring VM options for JavaFX when running the application.

Solution: Add the required module-path and module names in the VM options.