String parenthesis

import java.util.ArrayList;

public class GeneratePaqrenthesis {
    static void solve(ArrayList<String> output, int open, int close, String ans){
        if(open == 0 && close == 0){
            output.add(ans);
            return;
        }

        if(open>0){
            ans += "(";
            solve(output,open - 1, close, ans);
            ans.replace(String.valueOf(ans.charAt(ans.length()-1)),"");
        }

        if(close>open){
            ans += ")";
            solve(output,open , close-1, ans);
            ans.replace(String.valueOf(ans.charAt(ans.length()-1)),"");
        }
    }
    public static void main(String[] args) {

        int open = 2;
        int close = 2;
        String ans="";
        ArrayList<String> output = new ArrayList<>();

        solve(output,open,close,ans);
     for(String s:output){
         System.out.println(s);
     }

    }
}

//here the output is
//(()()
//(()) this is wrong with one extra ( braces