public final void setCenter(float x, float y, float z) {
        center.set(x, y, z);
    }
Returns a hash code. If two bounding volumes have identical values, they
will have the same hash code. The current instance is unaffected.

@return a 32-bit value for use in hashing
jme3-core/src/main/java/com/jme3/bounding/BoundingVolume.java