What is the difference between a rule switch and a regular switch in Java?

January 27, 2024

I couldn’t find this question anywhere else so I figured I might as well ask it. Is it purely aesthetic? Is it faster in any way? What are the main differences between the two? By regular switch, I mean

switch(var){
    case 1:
        break;
}

and by rule switch, I mean

switch(var){
    case 1 -> {}
}

>Solution :

In the regular switch you can omit to break the execution at the end of a code block. This allows a fall-through, and you can handle several different cases with the same code.

switch(var) {
    case 1:
      dosomething();
      break;
    case 2:
      dosomethindelse();
            // the break was forgotten
    case 3:
    case 4: // these cases shall work on the same code
      doanotherthing();
            // but the break was forgotten
    default:
      donothing();
}

This advantage is also a disadvantage since the break can easily be forgotten and then lead to difficult to spot bugs.

Therefore the rule switch was introduced, which – by it’s different syntax does not require a break and thus prevents such situations.