How do I induce collision events in LibGDX 3D?

In the code below I’ve put an example of something I want to do. I have the camera and I want it to stop moving whenever it hits one of the boxes, how do I do this?

public class Main extends ApplicationAdapter {

private final ModelBuilder builder = new ModelBuilder();
private final Environment environment = new Environment();
private ModelBatch modelBatch;
private PerspectiveCamera camera;
private Model model;
private ArrayList<ModelInstance> instance = new ArrayList<ModelInstance>();
private FirstPersonCameraController controller;
private BoundingBox[] boxBounds = new BoundingBox[1000];
private BoundingBox cameraBox = new BoundingBox();
private Vector3 cameraSpeed = new Vector3();
private Vector3 oldCameraPos = new Vector3();
private Vector3 newCameraPos = new Vector3();

@Override

public void create() {
    modelBatch = new ModelBatch();


    //build the camera
    camera = new PerspectiveCamera(67, graphics.getWidth(), graphics.getHeight());
    camera.position.set(0f, 10f, 0f);
    camera.lookAt(0, 10, 0);
    camera.near = 1f;
    camera.far = 1000f;
    camera.update();

    //build all the boxes
    for (int i = 0; i < 1000; i++) {
        model = builder.createBox(
                (float) Math.random() * 50,
                (float) Math.random() * 50,
                (float) Math.random() * 50,

                new Material(ColorAttribute.createDiffuse(

                        (float) random(),
                        (float) random(),
                        (float) random(), 1)
                ), Position | Normal);

        instance.add(new ModelInstance(model));
        instance.get(i).transform.setToTranslation(
                (float) random() * 1000 - 500,
                (float) random() * 1000,
                (float) random() * 1000 - 500);

        boxBounds[i] = new BoundingBox();
        boxBounds[i] = model.calculateBoundingBox(boxBounds[i]);
    }

    //build the ground
    model = builder.createBox(700f, 1f, 700f, new Material(ColorAttribute.createDiffuse(Color.GREEN)), Position | Normal);
    ModelInstance ground = new ModelInstance(model);
    instance.add(ground);

    //build the center
    model = builder.createBox(5f, 5f, 5f, new Material(ColorAttribute.createDiffuse(Color.RED)), Position | Normal);
    ModelInstance center = new ModelInstance(model);
    instance.add(center);


    //code the lights here
    DirectionalLight light = new DirectionalLight().set(255, 255, 255,
            (float) random(),
            (float) random(),
            (float) random());

    //set up the enviroment
    environment.set(new ColorAttribute(AmbientLight, 255f, 255f, 255f, 1f));
    environment.add(light);

    //set up the camera controller
    controller = new FirstPersonCameraController(camera);
    controller.setDegreesPerPixel(0.25f);
    controller.setVelocity(20);
    input.setInputProcessor(controller);
}

@Override
public void render() {
    //set up OpenGL
    gl.glViewport(0, 0, graphics.getWidth(), graphics.getHeight());
    gl.glEnable(GL_BLEND);
    gl.glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    gl.glClearColor(0, 0, 0, 0);

    //render the modelInstances
    modelBatch.begin(camera);
    modelBatch.render(instance, environment);
    modelBatch.end();
    controller.update();

    if (input.isKeyPressed(Input.Keys.R)) {
        camera.lookAt(0, 0, 0);
    }

    cameraSpeed = newCameraPos.sub(oldCameraPos);

    cameraBox = new BoundingBox(new Vector3(camera.position.x,
            camera.position.y,
            camera.position.z),

            new Vector3(camera.position.x + 10,
                    camera.position.y + 10,
                    camera.position.z + 10));

    for (int i = 0; i < 1000; i++) {
        if (cameraBox.contains(boxBounds[i])) {
            camera.position.x = camera.position.x - cameraSpeed.x;
            camera.position.y = camera.position.y - cameraSpeed.y;
            camera.position.z = camera.position.z - cameraSpeed.z;
        }
    }

    System.out.println(cameraSpeed.x + " " + cameraSpeed.y + " " + cameraSpeed.z);
}

@Override
public void dispose() {
    modelBatch.dispose();
    model.dispose();
}

}

Result: