Even if it is legal, mixing case and non-case labels in the body of a switch statement is very confusing, and can even be the result of a typing error.

Noncompliant Code Example

Case 1, the code is syntactically correct but the behaviour is not the expected one

switch (day) {
  case MONDAY:
  case TUESDAY:
  WEDNESDAY:   //instead of "case WEDNESDAY"
    doSomething();
    break;
  ...
}

Case 2, the code is correct and behaves as expected but is hardly readable

switch (day) {
  case MONDAY:
    break;
  case TUESDAY:
    foo:for(int i = 0 ; i < X ; i++) {
         /* ... */
        break foo;  //This break statement doesn't relate to the nesting case TUESDAY
         /* ... */
    }
    break;
    /* ... */
}

Compliant Solution

Case 1

switch (day) {
  case MONDAY:
  case TUESDAY:
  case WEDNESDAY:
    doSomething();
    break;
  ...
}

Case 2

switch (day) {
  case MONDAY:
    break;
  case TUESDAY:
    compute(args); //Put the content of the labelled "for" statement in a dedicated method
    break;

    /* ... */
}