Expression: IsLocked() == false, crashing when World is referenced?

Question

The Error

AL lib: (EE) alc_cleanup: 1 device not closed
Assertion failed!

Program: C:\Program Files\Java\jre1.8.0_25\bin\javaw.exe
File: /var/lib/jenkins/workspace/libgdx/extensions/gdx-box2d/gdx-box2d/jni/Box2D/Dynamics/b2World.cpp, Line 109

Expression: IsLocked() == false

The following line is the last line before the error occurs:

Body body = world.createBody(bodyDef);

I don't understand how this is causing a problem. world and bodyDef aren't null.

How my program is structured is that I have a GameStateRegular class that in its init method, it adds two new VirusEntity objects, like so:

VirusEntity virus0 = new VirusEntity(world, mother, new Vector2(0, 0));
VirusEntity virus1 = new VirusEntity(world, mother, new Vector2(100, 100));
viruses.add(virus0);
viruses.add(virus1);

And this works fine. I have a VirusEntity set to do the following code to do when it begins a Contact with the MotherCellEntity:

private void setContactListener() {
    world.setContactListener(new ContactAdapter() {
        @Override
        public void beginContact(Contact contact) {
            Body bodyA = contact.getFixtureA().getBody();
            Body bodyB = contact.getFixtureB().getBody();

            if (bodyA == mother.getBody()) work(bodyA, bodyB);
            else if (bodyB == mother.getBody()) work(bodyB, bodyA);
        }

        private void work(Body motherCellBody, Body virusBody) {
            VirusEntity virus = null;
            for (VirusEntity v : viruses) {
                if (v.getBody() == virusBody) virus = v;
            }
            virus.remove();
            VirusEntity newVirus = new VirusEntity(world, mother, virus.getSpawnPosition());
            viruses.add(newVirus);
        }
    });
}

I am referencing the same World object, and the same MotherCellEntity object to the new VirusEntity that is being created, but I still cannot tell what is going on here.

Full GameStateRegular class: http://pastebin.com/mFpmp28T
Full VirusEntity class: http://pastebin.com/HjSGS4ER

Thank you all in advanced for any help. I am being very vague on this topic because I really don't understand what's happening. I tried to do some background research on this, but I was unsuccessful.

Answer 1

How I was Successful

What I did was inside of my update method in my GameStateRegular class:

@Override
public void update() {
    world.step(1, 1, 1);
    mother.update();
    for (int i = 0; i < viruses.size(); i++) {
        VirusEntity e = viruses.get(i);
        if (e.isRemoved()) {
            viruses.remove(e);
            e.dispose();
            // --v--
            VirusEntity newVirus = new VirusEntity(world, mother, e.getSpawnPosition());
            viruses.add(newVirus);
            // --^--
        } else e.update();
    }
}

Also, for my ContactAdapter:

private void setContactListener() {
    world.setContactListener(new ContactAdapter() {

        @Override
        public void preSolve(Contact contact, Manifold manifold) {
            Body bodyA = contact.getFixtureA().getBody();
            Body bodyB = contact.getFixtureB().getBody();

            if (bodyA == mother.getBody()) virusInvolved(bodyA, bodyB);
            else if (bodyB == mother.getBody()) virusInvolved(bodyB, bodyA);
        }

        private void virusInvolved(Body motherCellBody, Body virusBody) {
            VirusEntity virus = null;
            for (VirusEntity v : viruses) {
                if (v.getBody() == virusBody) virus = v;
            }
            if (virus != null) {
                virus.setMovementAllowed(false);
                virus.remove();
            }
        }
    });
}