Performance of java if-else with return statement

private String getString1(int n){

    if (n == 0) {
        return "ZERO";
    }
    if (n == 1) {
        return "ONE";
    }
    if(n == 2) {
        return "TWO";
    }
    return "-NA-";
}

private String getString2(int n){

    if (n == 0) {
        return "ZERO";
    } else if (n == 1) {
        return "ONE";
    } else if(n == 2) {
        return "TWO";
    } else
        return "-NA-";
}

I have the above methods getString1(int) and getString2(int). Both will give the same o/p. But which one is the most efficient way of using? In there any difference in term of performance?