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This repository contains simple demo JavaFX 11+ applications, written in Kotlin.

The goal is to provide Kotlin/OpenJFX demo applications, which work out of the box. If they don't work - let me know! I hate demos that don't work.

All applications can be run from the command line, as long as the required software is installed (see Install section).

The list of demo apps includes:

  • Application 1 - Basic JavaFX/Kotlin Application
  • Application 2 - Drag and Drop
  • Application 3 - Nested Controllers, Event Based using Google EventBus
  • Application 4 - TableView Cell Value Factories vs Cell Factories
  • Application 5 - Custom Dialogs, an alternative to JavaFX official approach
  • Application 6 - Event Handling with helper and extension functions
  • Application 7 - Focus Functions

My blog on JavaFx with Kotlin at


All the code samples are not meant to be production quality and I use the following guidelines:

  • Enough unit tests to illustrate a point or technique
  • Logging, exception and error handling is avoided, unless it’s specifically a focus of the sample
  • Longer variable names to assist in clarity
  • Shorter classes and methods to minimise TL;DR syndrome.


You will need to install:

If you want to edit FXML and keep your sanity:

Dependency Management and Build - Gradle

Gradle is bundled as part of the project - no need to install anything.

Note: Remember the path of the OpenJFX install. I will refer to this as the JFX_INSTALL dir.


The projects does NOT need Gradle to be installed as this is included inside the project via a gradle wrapper

Set JFX_VERSION and JFX_INSTALL variable Values in build.gradle file

Find the section in the build.gradle:

    def JFX_VERSION = "13" // or "12" or "11"

and update the JFX_INSTALL value with your OpenJFX install directory.

Build The Applications

Build the applications with gradle:

gradlew clean build

Run all the unit and integration tests in headless mode

gradlew test

To run tests and show their execution with the TestFX robot use the showTests environment variable

gradlew test -DshowTests=true    

Application 1 - Basic JavaFx + Kotlin Application

  • Text Fields, Combo Boxes
  • ListView
  • TableView
  • Tabs
  • CSS Stylesheets
  • FXML based UI
  • TestFX tests

Start the application with:

gradlew runApp1

Application 2 - Drag and Drop

  • Drag and Drop between listView controls
  • Drag files from Desktop
  • Custom Drag images
  • CSS Stylesheets
  • FXML based UI
  • Drag and Drop TestFX tests

Start the application with:

gradlew runApp2

Application 3 - Multiple Controller + FXML files. Event Based Communication

  • Application with nested controllers/FXML
  • Controllers assigned dynamically, allowing dependency injection and better testing
  • Google EventBus used for publish-subscribe event communication between controllers
  • FXML based UI

Start the application with:

gradlew runApp3    

Application 4 - TableView Cell Factories vs Cell Value Factories

  • Examples of different Cell Value and Cell Factories in Kotlin
  • FXML based UI

Start the application with:

gradlew runApp4

Application 5 - Custom Dialogs

  • Simple, alternative custom dialog framework (2 classes!!) for creating custom dialogs
  • FXML based UI

Start the application with:

gradlew runApp5

Application 6 - Event Handlers

  • Add Kotlin style helper functions for adding event listeners to controls
  • Add Kotlin extension functions to the controls themselves for adding event listeners

Start the application with:

gradlew runApp6

Application 7 - Focus Handling

  • Add enter key processing, so hitting enter will now shift focus to next control - a UI tweak
  • Builds valid JDBC Urls for several databases as a side benefit!

Start the application with:

gradlew runApp7