Below is the code for one of my objects in the game I am creating (yes although this is a cube, I am not making anything remotely like MineCraft), and my issue is I while the cube will display and is does follow the physics if the cube falls, it does not interact with any other objects in the game. If I was to have multiple cubes in screen at once they all just sit there, or shoot off in all directions never stopping. Anyway, I am new to jBullet, and any help would be appreciated.

package Object;

import static org.lwjgl.opengl.GL11.GL_QUADS; import static org.lwjgl.opengl.GL11.glBegin; import static org.lwjgl.opengl.GL11.glColor3f; import static org.lwjgl.opengl.GL11.glEnd; import static org.lwjgl.opengl.GL11.glPopMatrix; import static org.lwjgl.opengl.GL11.glPushMatrix; import static org.lwjgl.opengl.GL11.glVertex3f;

import javax.vecmath.Matrix4f; import javax.vecmath.Quat4f; import javax.vecmath.Vector3f;

import com.bulletphysics.collision.shapes.BoxShape; import com.bulletphysics.collision.shapes.CollisionShape; import com.bulletphysics.dynamics.RigidBody; import com.bulletphysics.dynamics.RigidBodyConstructionInfo; import com.bulletphysics.linearmath.DefaultMotionState; import com.bulletphysics.linearmath.Transform;

public class Cube {

// Cube size/shape variables
private float size; 

boolean cubeCollidable;
boolean cubeDestroyable;

// Position variables - currently this defines the center of the cube
private float posX;
private float posY;
private float posZ;

// Rotation variables - should be between 0 and 359, might consider letting rotation go higher though I can't think of a purpose currently
private float rotX;
private float rotY;
private float rotZ;

//collision shape is a box shape
CollisionShape fallShape;

// setup the motion state for the ball
DefaultMotionState fallMotionState;
Vector3f fallInertia = new Vector3f(0, 1, 0);
RigidBodyConstructionInfo fallRigidBodyCI;

public RigidBody fallRigidBody;
int mass = 1;

// Constructor
public Cube(float pX, float pY, float pZ, float pSize)  {
    posX = pX;
    posY = pY;
    posZ = pZ;
    size = pSize;
    rotX = 0;
    rotY = 0;
    rotZ = 0;

    // define the physics based on the values passed in
    fallShape = new BoxShape(new Vector3f(size, size, size));
    fallMotionState = new DefaultMotionState(new Transform(new Matrix4f(new Quat4f(0, 0, 0, 1), new Vector3f(0, 50, 0), 1f)));
    fallRigidBodyCI = new RigidBodyConstructionInfo(mass, fallMotionState, fallShape, fallInertia);
    fallRigidBody = new RigidBody(fallRigidBodyCI);
}

public void Update() {
    Transform trans = new Transform();
    fallRigidBody.getMotionState().getWorldTransform(trans);

    posY = trans.origin.x;
    posX = trans.origin.y;
    posZ = trans.origin.z;
}

public void  Draw() {
    fallShape.calculateLocalInertia(mass, fallInertia);

    // center point posX, posY, posZ
    float radius = size / 2;

    //top
    glPushMatrix();
    glBegin(GL_QUADS);
        {
            glColor3f(1.0f,0.0f,0.0f); // red
            glVertex3f(posX + radius, posY + radius, posZ - radius);
            glVertex3f(posX - radius, posY + radius, posZ - radius);
            glVertex3f(posX - radius, posY + radius, posZ + radius);
            glVertex3f(posX + radius, posY + radius, posZ + radius);
        }
    glEnd();
    glPopMatrix();

    //bottom
    glPushMatrix();
    glBegin(GL_QUADS);
        {
            glColor3f(1.0f,1.0f,0.0f); // ?? color
            glVertex3f(posX + radius, posY - radius, posZ + radius);
            glVertex3f(posX - radius, posY - radius, posZ + radius);
            glVertex3f(posX - radius, posY - radius, posZ - radius);
            glVertex3f(posX + radius, posY - radius, posZ - radius);
        }
    glEnd();
    glPopMatrix();

    //right side
    glPushMatrix();
    glBegin(GL_QUADS);
        {
            glColor3f(1.0f,0.0f,1.0f); // ?? color
            glVertex3f(posX + radius, posY + radius, posZ + radius);
            glVertex3f(posX + radius, posY - radius, posZ + radius);
            glVertex3f(posX + radius, posY - radius, posZ - radius);
            glVertex3f(posX + radius, posY + radius, posZ - radius);
        }
    glEnd();
    glPopMatrix();

    //left side
    glPushMatrix();
    glBegin(GL_QUADS);
        {
            glColor3f(0.0f,1.0f,1.0f); // ?? color
            glVertex3f(posX - radius, posY + radius, posZ - radius);
            glVertex3f(posX - radius, posY - radius, posZ - radius);
            glVertex3f(posX - radius, posY - radius, posZ + radius);
            glVertex3f(posX - radius, posY + radius, posZ + radius);
        }
    glEnd();
    glPopMatrix();

    //front side 
    glPushMatrix();
    glBegin(GL_QUADS);
        {
            glColor3f(0.0f,0.0f,1.0f); //blue 
            glVertex3f(posX + radius, posY + radius, posZ + radius);
            glVertex3f(posX - radius, posY + radius, posZ + radius);
            glVertex3f(posX - radius, posY - radius, posZ + radius);
            glVertex3f(posX + radius, posY - radius, posZ + radius);
        }
    glEnd();
    glPopMatrix();

    //back side
    glPushMatrix();
    glBegin(GL_QUADS);
        {
            glColor3f(0.0f,1.0f,0.0f); // green
            glVertex3f(posX + radius, posY - radius, posZ - radius);
            glVertex3f(posX - radius, posY - radius, posZ - radius);
            glVertex3f(posX - radius, posY + radius, posZ - radius);
            glVertex3f(posX + radius, posY + radius, posZ - radius);
        }
    glEnd();
    glPopMatrix();
}

}