Java switch use case

user7294900 :

I'm reluctant to use a switch, but I saw switch will be improved in Java 12

Java 12 added the switch expression as an experimental feature. A Java switch expression is a switch statement which can return a value.

The only use case I found (before Java 12) where switch may be useful is returning different values from a small closed set of cases, e.g.:

    switch (input) {
    case "A":
        return "1";
    case "B":
        return "2";
    default:
        return "0";
    }

Or in Java 12 example:

return
switch(digitInDecimal){
    case  0 -> '0';
    case  1 -> '1';
    case  2 -> '2';
    default -> '?';

But I found an old but high-ranked answer that says to avoid multiple return statements:

Assigning a value to a local variable and then returning that at the end is considered a good practice. Methods having multiple exits are harder to debug and can be difficult to read.

So I wonder, is that answer still relevant due to switch changes?

Must I wait for Java 12 where switch can be used without temporary variables and breaks?

Andrew Tobilko :

Assigning a value to a local variable and then returning that at the end is considered a good practice.

I have no idea when it was considered a good practice. To me, switch is usually * an indicator that a design error was made. I would rather put my effort into thinking how to avoid a switch than into wondering how to return a value from a switch.

A few examples

Long list of if statements in Java
How to avoid switch-case statements in Java
Converting many 'if else' statements to a cleaner approach

Methods having multiple exits are harder to debug and can be difficult to read.

The same goes for a method that has a lot of breaks - that's what you are going to do if you choose the "local-variable approach".

In my opinion, none of these

// 1
switch (input) {
    case "A":
        return "1";
    case "B":
        return "2";
    default:
        return "0";
}

// 2
String varibleToReturn = null;
switch (input) {
    case "A":
        varibleToReturn = "1";
        break;
    case "B":
        varibleToReturn = "2";
        break;
    default:
        varibleToReturn = "0";
}
return varibleToReturn;

// 3
return switch(digitInDecimal) {
    case  0 -> '0';
    case  1 -> '1';
    case  2 -> '2';
    default -> '?';
}

makes a significant difference, or a slight improvement. Yes, Java-12's switch would give more conciseness and expressiveness, but the fundamental idea remains the same.

Must I wait for Java 12 where switch can be used without temporary variables and breaks?

What does it mean? :) No, the deadline is tomorrow, you have to work with what you've got at hand now.

---

*I am not underestimating the usefulness of switch. It may come in handy, for instance, when you programme at low-level, or you write an optimization.

I am just saying that in the real world, with Springs, and Hibernates, in a world of patterns, switch is obsolescent.