Does this method creates extra space?

I’m trying to reverse a stack without creating extra space.

This is what I came about:

{
                
    static Stack side = new Stack();
    static Object top = new Object();
    static Object bottom=new Object();
    static Stack st = new Stack();

    public static void main(String[] args) {
        st.push(1);
        st.push(2);
        st.push(3);
        st.push(4);
        st.push(5);
        st.push(6);
        st.push(7);
        st.push(8);
        st.push(9);
        reverse(st);
    }
    
  
    
    static void reverse(Stack st){
        top = st.peek();
        st.pop();
        transfer(st,side,bottom);
        addToButtom(st, top);
        bottom=st.peek();
        transfer(side,st,bottom);
        if (st.peek()!=top)reverse(st);
    }
    static void transfer(Stack st, Stack side, Object bottom){
        while (!st.empty()) {
            if (st.peek()!=bottom) {
                side.push(st.peek());
                st.pop();
            }else break;
        }
     }
    static void addToButtom(Stack st, Object top){st.push(top);}     
}

If this method creates extra space, how can I fix it?

Another question is, how can I modify so that the code run in O(n)?