Setting dock icon on OS X

extras/rhubarb-for-spine/src/main/kotlin/com/rhubarb_lip_sync/rhubarb_for_spine/MainApp.kt

@@ -1,5 +1,42 @@
 package com.rhubarb_lip_sync.rhubarb_for_spine
 
+import javafx.scene.image.Image
+import javafx.stage.Stage
 import tornadofx.App
+import tornadofx.addStageIcon
+import java.lang.reflect.Method
+import javax.swing.ImageIcon
 
-class MainApp : App(MainView::class)
+class MainApp : App(MainView::class) {
+	override fun start(stage: Stage) {
+		super.start(stage)
+		setIcon()
+	}
+
+	private fun setIcon() {
+		// Set icon for windows
+		for (iconSize in listOf(16, 32, 48, 256)) {
+			addStageIcon(Image(this.javaClass.getResourceAsStream("/icon-$iconSize.png")))
+		}
+
+		// OS X requires the dock icon to be changed separately.
+        // Not all JDKs contain the class com.apple.eawt.Application, so we have to use reflection.
+        val classLoader = this.javaClass.classLoader
+        try {
+            val iconURL = this.javaClass.getResource("/icon-256.png")
+            val image: java.awt.Image = ImageIcon(iconURL).image
+
+            // The following is reflection code for the line
+            // Application.getApplication().setDockIconImage(image)
+            val applicationClass: Class<*> = classLoader.loadClass("com.apple.eawt.Application")
+            val getApplicationMethod: Method = applicationClass.getMethod("getApplication")
+            val application: Any = getApplicationMethod.invoke(null)
+            val setDockIconImageMethod: Method =
+                applicationClass.getMethod("setDockIconImage", java.awt.Image::class.java)
+            setDockIconImageMethod.invoke(application, image);
+        } catch (e: Exception) {
+            // Works only on OS X
+        }
+	}
+
+}

extras/rhubarb-for-spine/src/main/kotlin/com/rhubarb_lip_sync/rhubarb_for_spine/MainView.kt

@@ -7,7 +7,6 @@ import javafx.beans.property.SimpleStringProperty
 import javafx.event.ActionEvent
 import javafx.event.EventHandler
 import javafx.scene.control.*
-import javafx.scene.image.Image
 import javafx.scene.input.DragEvent
 import javafx.scene.input.TransferMode
 import javafx.scene.text.Text
@@ -22,11 +21,6 @@ class MainView : View() {
 
 	init {
 		title = "Rhubarb Lip Sync for Spine"
-
-		// Set icon
-		for (iconSize in listOf(16, 32, 48, 256)) {
-			addStageIcon(Image(this.javaClass.getResourceAsStream("/icon-$iconSize.png")))
-		}
 	}
 
 	override val root = form {