Unable to get behaviour of Switch case in java

Question

I have written small code in java 6

public class TestSwitch{

public static void main(String... args){
    int a = 1;
    System.out.println("start");
          


        

Answer 1

switch(a){
    case 1:{
        System.out.println(1);
        case 3:

You cannot nest cases like this. Switch should look either like :

    switch(a){
    case 1:
        System.out.println(1);
        break;
    case 3:
       ....

or like this :

switch(a){
    case 1:
        System.out.println(1);
        switch(a) {
            case 3:
                //...
                break;
            case 5 :
                //...

And if you don't add break at the end of a case, the execution will continue after. You should add a break at the end of each cases if they should be executed separately.