children = new ArrayList<Spatial>();
children = new ArrayList<Spatial>(1);
    public int attachChildAt(Spatial child, int index) {        if (child != null) {            if (child.getParent() != this) {                if (child.getParent() != null) {                    child.getParent().detachChild(child);                }                child.setParent(this);                if(children == null) {                    children = new ArrayList<Spatial>();                  }                children.add(index, child);                if (LoggingSystem.getLogger().isLoggable(Level.INFO)) {                    LoggingSystem.getLogger().log(                            Level.INFO,                            "Child (" + child.getName() + ") attached to this"                                    + " node (" + getName() + ")");                }            }        }        return children.size();    }