Question

So I’m still pretty new to Java and I’m trying to make a game. I’ve created a really basic game engine using a tutorial online. I have three classes, Engine(the core), Sprite, SpriteManager. Each of these classes is described in their own .java file inside one package. I am using NetBeans and I would like to create another .java to sort of handle the frontend of the game; something that extends the Application class of what I believe is JavaFX. The only problem is that when I create this file and attempt to run the game I get this message in the debug console:

run:
java.lang.NoSuchMethodException: kingdomsclash.Engine.main([Ljava.lang.String;)
    at java.lang.Class.getMethod(Class.java:1622)
    at com.javafx.main.Main.launchApp(Main.java:656)
    at com.javafx.main.Main.main(Main.java:805)
Java Result: 1
jfxsa-run:
BUILD SUCCESSFUL (total time: 4 seconds)

It appears that NB isn’t even trying to run my FrontEnd file and is instead using Engine.java even though Engine is just a class declaration. FrontEnd is simply the hello world template created by NB when you create a new Main Class java file; it does not instantiate any of the other classes.

TL;DR

1. How do I make the java app run FrontEnd first or otherwise fix the error above?

Thank you very much for your help. If you need any other info, don’t hesitate to ask. 🙂

Answer 1

In NetBeans, you can go to File | Project Properties | Run and change the Application class field to match your kingdomclash.FrontEnd class (which should have a main method in it, extend JavaFX Application and also have a start method).

As long as you set the project up as JavaFX project originally, it should work.

If it’s just a plain Java project, NetBeans may not find the JavaFX runtime, in which case you can follow the instructions below. If your existing code is written for Swing I would advise rewriting it for JavaFX rather than trying to mix the two systems which will bring unwanted complexity when you are first starting out.

NetBeans has special project and platform types for JavaFX applications, which you should be using (otherwise it won’t find the javafx runtime). There is documentation on how to set it up (but unfortunately it is currently outdated as it does not refer to the current JavaFX 2.2 release, but instead to an older JavaFX 2.1 release for which the platform setup is more complicated). Basically, what you need to do is use a recent Java version (jdk 7.7u6+) with a recent NetBeans version (7.2+) and choose new Project | JavaFX | JavaFX Application. NetBeans should create a basic hello world skeleton you can run. Copy and paste your game code into that, make sure it uses only JavaFX classes not java awt or swing classes, and you should be good to go.

You may also be interested in this really neat tutorial on creating sprite animations with JavaFX.