Java scanner return value not properly compareable [duplicate]

This question already has an answer here:

• How do I compare strings in Java? 23 answers

    import java.util.Scanner;

    public static void main(String[] args){
        Scanner input = new Scanner(System.in);

        // Attempt 1
        String r = input.next();
        if(r=="bu") {
            System.out.println("- application terminated - ended by user");
            System.exit(0);
        }

        // Attempt 2
        String r = "bu";
        if(r=="bu"){
            System.out.println("- application terminated - ended by user");
            System.exit(0);
        }
    }

Thats the stripped down code.

Attempt 1 didnt work, even tho the scanner did get the input "bu" from the console right (checked that by printing out r). Yet somehow the if-clause was not executed (The sysout wasnt even printed).

With Attempt 2 it worked perfectly, so something has to be wrong with the scanner or its detected value in Attempt 1, but I wasnt able to determine what.

Unfortunately the scanner is mandatory for the task, so how can I fix it? Please help!