Palindrome using java stringbuilder

Question

public class testing {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine();
        StringBuilder sb = new StringBuilder();
        StringBuilder sb1 = new StringBuilder();
        sb.append(str);
        sb1.append(str);
        sb1.reverse();
        if(sb == sb1) {
            System.out.println("yes");
        }else if(sb != sb1) {
            System.out.println("no");
        }
        System.out.println(sb.length());
        System.out.println(sb1.length());
        sc.close();
    }
}

Everything working fine including string reverse, but always getting no as result.

Answer 1

You will always get no because StringBuilder creates new object & as you are using == for comparison, it compares reference only not content of StringBuilder object, so if you want to compare content you have to use .equals() method after applying .toString() on StringBuilder object.