Libgdx Box2d Java Crash - jniCreateBody

Question

I'm playing with Libgdx since a while now, but encountered this problem the first time.

My Problem: Java environment crashes when I try to create a Body. Error Log:

Java frames: (J=compiled Java code, j=interpreted, Vv=VM code) 
    j com.badlogic.gdx.physics.box2d.World.jniCreateBody(JIFFFFFFFFZZZZZF)J+0
j  com.badlogic.gdx.physics.box2d.World.createBody(Lcom/badlogic/gdx/physics/box2d/BodyDef;)Lcom/badlogic/gdx/physics/box2d/Body;+80
j  xxx.xx.box2dTest.Enteties.SmallBee.init(FF)V+60
j  xxx.xx.box2dTest.Enteties.SmallBee.<init>(Lcom/badlogic/gdx/physics/box2d/World;Lcom/badlogic/gdx/graphics/OrthographicCamera;)V+112
J 1268 C1 xxx.xx.box2dTest.Organization.Ingame.Level.BossOne.BossOneWorld.spawnSmallBee()V (48 bytes) @ 0x000000000323e174 [0x000000000323dec0+0x2b4]
j  xxx.xx.box2dTest.Organization.Ingame.Level.BossOne.BossOne.extraStuff()V+223
J 1176 C1 xxx.xx.box2dTest.Organization.Ingame.Level.MotherLevel.render(F)V (269 bytes) @ 0x00000000031e1a0c [0x00000000031e0460+0x15ac]
J 1175 C1 xxx.xx.box2dTest.Organization.Ingame.Level.BossOne.BossOne.render(F)V (499 bytes) @ 0x00000000031d994c [0x00000000031d98c0+0x8c]
J 1144 C1xxx.xx.box2dTest.Box2DGame.render()V (5 bytes) @ 0x00000000031cb744 [0x00000000031cb520+0x224]
j  com.badlogic.gdx.backends.lwjgl.LwjglApplication.mainLoop()V+684
j  com.badlogic.gdx.backends.lwjgl.LwjglApplication$1.run()V+27
v  ~StubRoutines::call_stub

What I do: I create every now and then a body. Most of the time all is okay, still crashes SOME times.. The first creation never failed until now.

  public void spawnSmallBee(){
    if(TimeUtils.millis() - smallBeeTimer > 0){
        new SmallBee(getWorld(), getCamera());
        smallBeeTimer = TimeUtils.millis() + MathUtils.random(2000, 3000);
    }
}

this code snippet is where I create the Object, that will create the Body

public SmallBee(World world, OrthographicCamera camera) {
    this.world = world;
    this.camera = camera;
    MOVING_SPEED_Y= MathUtils.random(-3, 3);

    sprite = new Sprite(MyAssets.SMALL_BEE);
    sprite.setSize(WIDTH * 2, HEIGHT * 2);
    sprite.setOriginCenter();
    myEntity = new MyEntity("Bee", sprite);
    myEntity.setObject(this);

    float posx = camera.position.x - camera.viewportWidth / 2 - 2;
    float posy = MathUtils.random(1, 7);

    BodyDef platformDef = new BodyDef();
    platformDef.type = BodyDef.BodyType.KinematicBody;
    platformDef.position.set(posx, posy);
    body = world.createBody(platformDef);
    PolygonShape platformBox = new PolygonShape();
    platformBox.setAsBox(WIDTH, HEIGHT);

    body.createFixture(platformBox, 0.0f);

    body.setLinearVelocity(new Vector2(MOVING_SPEED_X, MOVING_SPEED_Y));
    myEntity.getSprite().setPosition(body.getPosition().x - WIDTH, body.getPosition().y - HEIGHT);
    body.setUserData(myEntity);
    // Remember to dispose of any shapes after you're done with them!
    // BodyDef and FixtureDef don't need disposing, but shapes do.
    platformBox.dispose(); }

this code snippet is the creation of the Object

As example, i got nearly the same Object, that doesnt crash

creation is one line before bee creation

public void spawnArrowShooter() {
    if(TimeUtils.millis() - arrowShooterTimer > 0){
        new ArrowShooter(getWorld(), MathUtils.random(200 - getCamera().viewportWidth / 2 + 2, 200 + getCamera().viewportWidth / 2 - 2), 3, getPlayer(), getCamera(), bossWasp);
        arrowShooterTimer = TimeUtils.millis() + MathUtils.random(10000, 15000);
    }
}

the initiation:

 public ArrowShooter(World world, float x, float y, Player player, OrthographicCamera camera, BossWasp bossWasp) {
    this.camera = camera;
    this.bossWasp = bossWasp;
    //PLATTFORM
    this.world = world;
    this.player = player;

    sprite = new Sprite(MyAssets.ARROW);
    sprite.setSize(WIDTH * 2, HEIGHT * 2);

    myEntity = new MyEntity("Arrow", sprite);
    myEntity.setObject(this);



    init(x, y);

}


 public void init(float x, float y){
    BodyDef platformDef = new BodyDef();
    // We set our body to dynamic, for something like ground which doesn't move we would set it to StaticBody
    platformDef.type = BodyDef.BodyType.DynamicBody;

    platformDef.position.set(x, y);
    body = world.createBody(platformDef);
    PolygonShape platformBox = new PolygonShape();
    platformBox.setAsBox(WIDTH, HEIGHT);
    Fixture fixture = body.createFixture(platformBox, 0.0f);
    myEntity.getSprite().setPosition(body.getPosition().x - WIDTH, body.getPosition().y - HEIGHT);

    body.setUserData(myEntity);
    // Remember to dispose of any shapes after you're done with them!
    // BodyDef and FixtureDef don't need disposing, but shapes do.
    platformBox.dispose();
    disappearTime = TimeUtils.millis() + 4000;
}

I cant figure the problem out..

if(world.isLocked()){
  return;
}

doesnt help either.

The body is 100% not created on another Object.

I'll try to investigate the Problem further, and provide any new informations that I could gather.

Please try to help me!

Answer 1

I realised, that I could spawn millions of Bees in seconds, without Problems, so I created about 10 every second. No crashes, till the arrow hit the Boss and got destroyed - immidiately game crash.

I watched earlier for some destroyed body modification, but I missed one line..

The problem was: I had set the velocity from a destroyed body!

No more crashes until now.

As I had read in another Forum:

"When you destroy a body, do: body = null This will help you to find your fault, if not you may get some hard to understand errors"

Hope you can get help from this.