Getting an error message - "java.base/java.lang.StringConcatHelper.simpleConcat(StringConcatHelper.java:421)"

Question

Hello Guys I was making a program of "Generate all parenthesis" and I got the error message as:-"java.base/java.lang.StringConcatHelper.simpleConcat(StringConcatHelper.java:421)"

along with this I am getting error of stack overflow

I am attaching a code with this error please see to it and tell me the modification if needed:-

public class j{
public static void main(String[] args){
    int n = 2;
    int open = n;
    int close = n;
    String op = " ";
    findAns(op, open, close);
}
private static void findAns(String op, int open, int close){
    if (open == 0 && close == 0){
        System.out.println(op);
    }
    
    if (open == close){
        String op1 = op + "(";
        findAns(op1, open - 1, close);
        return;
    }
    if (open != 0){
        String op1 = op + "(";
        open = open - 1;
        findAns(op1, open, close);
    }
    String op1 = op + ")";
    close = close - 1;
    findAns(op1, open, close);
    return;
}   }

Answer 1

You need an exit condition for your recursion. Maybe this?

if (open == 0 && close == 0){
    System.out.println(op);
--> return;
}