Flow Control - SCJP Sun Certified Programmer for Java Platform SE6 - page 193

The last rule is what makes a switch statement unique. The value being switched on is
compared for equality to each case statement in the order that they appear. Once a case
statement is true , no subsequent case statements are tested. All statements following a true
case execute, even if control “falls through” other case statements, until a break occurs.
Let's look at an example. The following code switches on an int . See if you can
determine the output:
6. int x = 0;
7. switch(x) {
8. case 0 :
9. case 1 :
10. System.out.println(“0 or 1”);
11. break;
12. case 2 :
13. System.out.println(“2”);
14. case 3 :
15. System.out.println(“2 or 3”);
16. break;
17. default :
18. System.out.println(“default”);
19.}
20.System.out.println(“After switch”);
Here is the fl ow of control that occurs when this code executes:
1. The int x is declared and assigned the value 0 .
2. The case 0 is true on line 8, so no more cases are tested for equality.
3. x does not equal 1 on line 9, but x is not compared to 1 on line 9. Instead, control just
falls through to line 10.
4. 0 or 1 is printed on line 10.
5. The break is hit on line 11, causing control to jump out of the switch statement down
to line 20 and After switch is printed.
Therefore, the output of this switch is
0 or 1
After switch
Using the same switch statement, the following output displays when x equals 2 :
2
2 or 3
After switch