How can the same expression be evaluated differently?

Question

Can someone please shed some light on this sick sorcery:

    System.out.println(("a".equals("a")));  //true
    System.out.println(("a".equals("а")));  //false

    System.out.println(("Joachim Garraud" == "Joachim Garraud"));       //true
    System.out.println(("Joachim Garraud" == "Joаchim Garraud"));       //false
    System.out.println(("Joachim Garraud".equals("Joаchim Garraud")));  //false
    System.out.println(("Joachim Garraud".equals("Joachim Garraud")));  //true

I have no idea what is going on here, but I swear I get these results. I really don't see any difference, and the results are consistent - also when I copy a "false-line", I get false again and vice versa.

Answer 1

I suspect that the cause is that your code contains different versions of (for instance) the "a" character. For instance, a lower-case LATIN A could look identical to a lower-case CYRILIC A ... but they are different Unicode code points (\u0061 versus \u0430), and therefore not equal.