Why do I get the "Selection does not contain a main type" when my class has a main?

Question

I get the above error msg but my class does have a main method:

package adventure;
import com.jme3.system.AppSettings;
import java.applet.Applet;
import java.applet.AudioClip;
import java.awt.Image;
import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import com.jme3.renderer.queue.RenderQueue.ShadowMode;
import com.jme3.animation.AnimChannel;
import com.jme3.animation.AnimControl;
import com.jme3.animation.AnimEventListener;
import com.jme3.animation.LoopMode;
import com.jme3.app.SimpleApplication;
import com.jme3.asset.BlenderKey;
import com.jme3.asset.plugins.HttpZipLocator;
import com.jme3.asset.plugins.ZipLocator;
import com.jme3.bullet.BulletAppState;
import com.jme3.bullet.PhysicsSpace;
import com.jme3.bullet.collision.shapes.CapsuleCollisionShape;
import com.jme3.bullet.control.CharacterControl;
import com.jme3.bullet.control.RigidBodyControl;
import com.jme3.input.ChaseCamera;
import com.jme3.input.KeyInput;
import com.jme3.input.controls.ActionListener;
import com.jme3.input.controls.KeyTrigger;
import com.jme3.light.AmbientLight;
import com.jme3.light.DirectionalLight;
import com.jme3.material.MaterialList;
import com.jme3.math.ColorRGBA;
import com.jme3.math.Vector3f;
import com.jme3.post.FilterPostProcessor;
import com.jme3.post.filters.BloomFilter;
import com.jme3.scene.Node;
import com.jme3.scene.Spatial;
import com.jme3.scene.plugins.ogre.OgreMeshKey;
import com.jme3.input.controls.MouseButtonTrigger;
import com.jme3.input.MouseInput;
public class Q3World extends SimpleApplication implements ActionListener,
        AnimEventListener, Playable {
    private Node gameLevel;
    //private PhysicsCharacter player;
    private static boolean useHttp = false;
    //private static World world;
    //private static Person person;
    //private static Player dplayer;
    private BulletAppState bulletAppState;
    private AnimChannel channel;
    private AnimControl control;
    // character
    CharacterControl character;
    CharacterControl goblincharacter;
    Node model;
    // temp vectors
    Vector3f walkDirection = new Vector3f();
    Spatial goblin;
    RigidBodyControl terrainPhysicsNode;

    // animation
    AnimChannel animationChannel;
    AnimChannel shootingChannel;
    AnimControl animationControl;
    float airTime = 0;
    // camera
    boolean left = false, right = false, up = false, down = false, attack=false;
    ChaseCamera chaseCam;

    FilterPostProcessor fpp;
    private Spatial sceneModel;

    private RigidBodyControl landscape;

    public static void main(String[] args) {

        File file = new File("quake3level.zip");
        if (!file.exists()) {
            useHttp = true;
        }
        Q3World app = new Q3World();
        AppSettings settings = new AppSettings(true);
        settings.setTitle("Dungeon World");
        settings.setSettingsDialogImage("Interface/splash.png");
        app.setSettings(settings);

        app.start();
    }

    @Override
    public void simpleInitApp() {
        bulletAppState = new BulletAppState();
        bulletAppState.setThreadingType(BulletAppState.ThreadingType.PARALLEL);
        stateManager.attach(bulletAppState);
        setupKeys();
        DirectionalLight dl = new DirectionalLight();
        dl.setColor(ColorRGBA.White.clone().multLocal(2));
        dl.setDirection(new Vector3f(-1, -1, -1).normalize());
        rootNode.addLight(dl);
        AmbientLight am = new AmbientLight();
        am.setColor(ColorRGBA.White.mult(2));
        rootNode.addLight(am);

        if (useHttp) {
            assetManager
                    .registerLocator(
                            "http://jmonkeyengine.googlecode.com/files/quake3level.zip",
                            HttpZipLocator.class);
        } else {
            assetManager.registerLocator("quake3level.zip", ZipLocator.class);
        }

        // create the geometry and attach it
        MaterialList matList = (MaterialList) assetManager
                .loadAsset("Scene.material");
        OgreMeshKey key = new OgreMeshKey("main.meshxml", matList);
        gameLevel = (Node) assetManager.loadAsset(key);
        gameLevel.setLocalScale(0.1f);
        gameLevel.addControl(new RigidBodyControl(0));
        getPhysicsSpace().addAll(gameLevel);
        rootNode.attachChild(gameLevel);
        getPhysicsSpace().addAll(gameLevel);
        createCharacters();
        setupChaseCamera();
        setupAnimationController();
        setupFilter();
    }

    private void setupFilter() {
        FilterPostProcessor fpp = new FilterPostProcessor(assetManager);
        BloomFilter bloom = new BloomFilter(BloomFilter.GlowMode.Objects);
        fpp.addFilter(bloom);
        viewPort.addProcessor(fpp);
    }

    private PhysicsSpace getPhysicsSpace() {
        return bulletAppState.getPhysicsSpace();
    }

    private void setupKeys() {
        inputManager.addMapping("wireframe", new KeyTrigger(KeyInput.KEY_T));
        inputManager.addListener(this, "wireframe");
        inputManager.addMapping("CharLeft", new KeyTrigger(KeyInput.KEY_A));
        inputManager.addMapping("CharRight", new KeyTrigger(KeyInput.KEY_D));
        inputManager.addMapping("CharUp", new KeyTrigger(KeyInput.KEY_W));
        inputManager.addMapping("CharDown", new KeyTrigger(KeyInput.KEY_S));
        inputManager.addMapping("CharSpace",
                new KeyTrigger(KeyInput.KEY_SPACE));
        inputManager
                .addMapping("CharShoot",  new MouseButtonTrigger(MouseInput.BUTTON_LEFT));
        inputManager.addListener(this, "CharLeft");
        inputManager.addListener(this, "CharRight");
        inputManager.addListener(this, "CharUp");
        inputManager.addListener(this, "CharDown");
        inputManager.addListener(this, "CharSpace");
        inputManager.addListener(this, "CharShoot");
    }

    private void createCharacters() {
        CapsuleCollisionShape capsule = new CapsuleCollisionShape(0.05f, 0.05f);
        character = new CharacterControl(capsule, 2);
        character.setJumpSpeed(20f);
        model = (Node) assetManager.loadModel("Models/Ninja/Ninja.mesh.xml");
        model.scale(0.05f, 0.05f, 0.05f);
        model.addControl(character);
        character.setPhysicsLocation(new Vector3f(55, 15, -60));
        model.setShadowMode(ShadowMode.CastAndReceive);
        character.setViewDirection(new Vector3f(1, 0, 0));
        rootNode.attachChild(model);
        getPhysicsSpace().add(character);
        BlenderKey blenderKey = new BlenderKey("Models/Oto/Oto.mesh.xml");
        Spatial man = (Spatial) assetManager.loadModel(blenderKey);
        man.setLocalTranslation(new Vector3f(67, 15, -60));
        man.setShadowMode(ShadowMode.CastAndReceive);
        rootNode.attachChild(man);

        goblin = assetManager.loadModel("objects/goblin.j3o");

        goblin.scale(4f, 4f, 4f);
        //goblin.setLocalTranslation(60, 3.5f, -60);
        goblincharacter = new CharacterControl(capsule, 2);
        goblin.addControl(goblincharacter);
        goblincharacter.setPhysicsLocation(new Vector3f(60, 3.5f, -60));
        //goblincharacter.setViewDirection(new Vector3f(1, 0, 0));
        //character.setWalkDirection(new Vector3f(1, 0, 0));



        control = goblin.getControl(AnimControl.class);
        control.addListener(this);
        channel = control.createChannel();

        for (String anim : control.getAnimationNames())
            System.out.println("goblin can:"+anim);
        channel.setAnim("walk");

        rootNode.attachChild(goblin);
        getPhysicsSpace().add(goblincharacter);
        Spatial monster = assetManager.loadModel("objects/creatures/monster/monster.packed.j3o");

        Spatial monster2 = assetManager.loadModel("Models/Jaime/Jaime.j3o");
        monster2.scale(5f, 5f, 5f);
        monster.scale(2f, 2f, 2f);
        monster.setLocalTranslation(new Vector3f(53, 3, -55));
        monster2.setLocalTranslation(new Vector3f(50, 3, -55));

        rootNode.attachChild(monster2);
        rootNode.attachChild(monster);

    }

    private void setupChaseCamera() {
        flyCam.setEnabled(false);
        chaseCam = new ChaseCamera(cam, model, inputManager);
        chaseCam.setDefaultDistance(27);



    }

    private void setupAnimationController() {
        animationControl = model.getControl(AnimControl.class);
        animationControl.addListener(this);
        animationChannel = animationControl.createChannel();
        //shootingChannel = animationControl.createChannel();

    }

    @Override
    public void simpleUpdate(float tpf) {

        goblincharacter.setWalkDirection(goblin.getLocalRotation().mult(Vector3f.UNIT_Z).multLocal(0.4f));
        Vector3f camDir = cam.getDirection().clone().multLocal(0.1f);
        Vector3f camLeft = cam.getLeft().clone().multLocal(0.1f);
        camDir.y = 0;
        camLeft.y = 0;
        walkDirection.set(0, 0, 0);
        if (left) {
            walkDirection.addLocal(camLeft);
        }
        if (right) {
            walkDirection.addLocal(camLeft.negate());
        }
        if (up) {
            walkDirection.addLocal(camDir);
        }
        if (down) {
            walkDirection.addLocal(camDir.negate());
        }
        //if (attack) {
            //animationChannel.setAnim("Attack1");
            //animationChannel.setLoopMode(LoopMode.DontLoop);
        //}
        if (!character.onGround()) {
            airTime = airTime + tpf;
        } else {
            airTime = 0;
        }
        if (walkDirection.length() == 0) {
            if (!"Idle1".equals(animationChannel.getAnimationName())) {
                animationChannel.setAnim("Idle1", 1f);
            }
        } else {            
            character.setViewDirection(walkDirection.negate());
            if (airTime > .3f) {
                if (!"stand".equals(animationChannel.getAnimationName())) {
                    animationChannel.setAnim("Idle1");
                }
            } else if (!"Walk".equals(animationChannel.getAnimationName())) {
                animationChannel.setAnim("Walk", 1f);
            }
        }
        character.setWalkDirection(walkDirection);
    }

    /*Ninja can: Walk
Ninja can: Kick
Ninja can: JumpNoHeight
Ninja can: Jump
Ninja can: Spin
Ninja can: Attack1
Ninja can: Idle1
Ninja can: Attack3
Ninja can: Idle2
Ninja can: Attack2
Ninja can: Idle3
Ninja can: Stealth
Ninja can: Death2
Ninja can: Death1
Ninja can: HighJump
Ninja can: SideKick
Ninja can: Backflip
Ninja can: Block
Ninja can: Climb
Ninja can: Crouch*/

    public void onAction(String binding, boolean value, float tpf) {



        if (binding.equals("CharLeft")) {
            if (value) {
                left = true;
            } else {
                left = false;
            }
        } else if (binding.equals("CharRight")) {
            if (value) {
                right = true;
            } else {
                right = false;
            }
        } else if (binding.equals("CharUp")) {
            if (value) {
                up = true;
            } else {
                up = false;
            }
        } else if (binding.equals("CharDown")) {
            if (value) {
                down = true;
            } else {
                down = false;
            }
        } else if (binding.equals("CharSpace")) {
            character.jump();
        } else if (binding.equals("CharShoot") && value) {
            //bulletControl();
            Vector3f origin    = cam.getWorldCoordinates(inputManager.getCursorPosition(), 0.0f);
            Vector3f direction = cam.getWorldCoordinates(inputManager.getCursorPosition(), 0.0f);
            //direction.subtractLocal(origin).normalizeLocal();
            //character.setWalkDirection(location);
            System.out.println("origin"+origin);
            System.out.println("direction"+direction);
            //character.setViewDirection(direction);
            animationChannel.setAnim("Attack3");
            animationChannel.setLoopMode(LoopMode.DontLoop);
        }
    }

    public void onAnimCycleDone(AnimControl control, AnimChannel channel,
            String animName) {
        if (channel == shootingChannel) {
            channel.setAnim("Idle1");
        }
    }

    public void onAnimChange(AnimControl control, AnimChannel channel,
            String animName) {
    }

    // Load an image from the net, making sure it has already been
    // loaded when the method returns
    public Image loadPicture(String imageName) {
        return null;
    }

    // Load and play a sound from /usr/local/hacks/sounds/
    public void playSound(String name) {
        URL u = null;
        try {
            u = new URL("file:" + "/usr/local/hacks/sounds/" + name + ".au");
        } catch (MalformedURLException e) {
        }
        AudioClip a = Applet.newAudioClip(u);
        a.play();
    }
}

Since this only happens on windows 7 and not on ubuntu where the code was written, I suppose it's some setting or build path in eclipse juno for windows 7 but which setting is it that I must set?

Answer 1

Try cleaning and rebuilding your project. Also make sure that your .java files are in the .src folder.

Also Check if your source folder exists in the project properties -> java build path -> source.

Answer 2

you main.java should be in the source file it happened to me once i moved it and the problem was solver