Prepare JavaFX with Gradle.

start program with 'gradle run'

build.gradle

@@ -1,10 +1,16 @@
-apply plugin: 'java'
-apply plugin: 'idea'
+plugins {
+    id 'java'
+    id 'idea'
+    id 'application'
+    id 'org.openjfx.javafxplugin' version '0.0.7'
+}
 
 compileJava.options.encoding = 'UTF-8'
 
 project.ext.junitVersion = '5.3.1'
 
+mainClassName = '_9.HelloWorld'
+
 sourceCompatibility = 1.8
 
 repositories {
@@ -16,6 +22,11 @@ dependencies {
     testRuntimeOnly "org.junit.jupiter:junit-jupiter-engine:$junitVersion"
 }
 
+javafx {
+    version = "12.0.1"
+    modules = [ 'javafx.controls' ]
+}
+
 test {
     useJUnitPlatform()
 }