The requirement for a final default clause is defensive programming. The clause should either take appropriate action, or contain a
suitable comment as to why no action is taken.
Noncompliant code example
switch (param) { //missing default clause
case 0:
doSomething();
break;
case 1:
doSomethingElse();
break;
}
switch (param) {
default: // default clause should be the last one
error();
break;
case 0:
doSomething();
break;
case 1:
doSomethingElse();
break;
}
Compliant solution
switch (param) {
case 0:
doSomething();
break;
case 1:
doSomethingElse();
break;
default:
error();
break;
}
Exceptions
If the switch parameter is an Enum and if all the constants of this enum are used in the case statements,
then no default clause is expected.
Example:
public enum Day {
SUNDAY, MONDAY
}
...
switch(day) {
case SUNDAY:
doSomething();
break;
case MONDAY:
doSomethingElse();
break;
}
