Question: I created a setup by Advanced Installer software for my program that I've written by c#. I installed my program on VMWare Windows7.

When I try to run it this message is displayed:

![Class not registered](https://i.stack.imgur.com/efAyh.png)

Answer: 
It would be a good idea to add a default case to your switch statement.

Example:

```
switch (monthNumber) {
    case 1: monthString = "January";
        break;

    //other cases...

    default: monthString = "Invalid Month Number";
        break;
}

```

This way if `monthNumber` is not 1-12 then there is still a default case for the switch statement to flow to.
Because the designer of Java language believes it made more sense for it to be! Codes are easier to read when variables are initialised. A statement `String foo;` feels non-deterministic because you have to guess what's the default value of String is whereas `String foo = null;` is more deterministic.

To give you a more obvious example, consider this:

```
int x;
Int y;

```

Can you very quickly guess what the default values are? You probably have to pause for a few second to realize x is probably 0 and y is probably null