When calling if statement in another class from if statement condition, why does it make it loop?

So I have this code,

public class testestest {
    public static void main (String[]args) {
        int b=2;
        tst tst = new tst();    

        if (tst.tst(b)==1) { 
            System.out.println("a=1");
        }
        else if (tst.tst(b)==2) {
            System.out.println("a=2");
        }
        else if (tst.tst(b)==3) {
            System.out.println("a=3");
        }
    }
}

class tst {
    int tst (int b) {
        if (b==2) {
            System.out.println("print2");
            return b;
        }
        if (b==3) {
            System.out.println("print3");
            return b;
        }
        return 0;
    }
}

when you execute it it prints print2 print2 a=2. If I change int b to 3, then it prints print3 print3 print3 a=3. I am not sure as to why tst.tst(b) method loops if statement in tst class for the number of b.
Can somebody explain to me why it's doing this? Also, how could I change my code so that it doesn't loop, but rather execute the method only once?