two string instances seems same, but their hashcode are different

Question

    String a = "success";
    String b = "success";

    System.out.println(a.hashCode());
    System.out.println(b.hashCode());

    if(a.equals(b)){
        System.out.println("123");
    }

I can't understand why the two string have different hashcode.

    String a = "success";
    String b = "success";

    System.out.println(a.hashCode());
    System.out.println(b.hashCode());

    System.out.println(System.identityHashCode(a));
    System.out.println(System.identityHashCode(b));

output:

-1867169789
1954952228
33263331
6413875

Answer 1

You've inserted the zero width no-break space (U+FEFF) character at the beginning of your second string.

That string is actually equal to the following string (no hidden unicode characters): "\ufeffsuccess"

That means a and b are not equal and do not have the same hash code.