Where can i use a try/catch block in my game? - exception

Question

This is my game i created, i just need to add a try catch into it somehow and i am stuck.
/**
*
* #author
*/
import java.util.*;
public class magiceightball {
public static void main (String [] args){
questions();
}
public static void questions(){ //method
Scanner input = new Scanner(System.in);
while(true){
System.out.println();
System.out.println("Welcome to the Magic 8 Ball Game!");
System.out.println("Shake(Type 'Shake' to have you question answered, or type 'No more'to end the game");
String request = input.nextLine();
I think here is where i can add a try
if (request.equalsIgnoreCase("shake")){
answer();
}
else if(request.equalsIgnoreCase("No more")){
break;
}
else{
System.out.println("Invalid answer. Please try again!");
}
}
}
public static void answer(){
switch(shake()){
case 1:System.out.println("It is certain");
break;
case 2:System.out.println("It is decidedly so");
break;
case 3:System.out.println("Most likely");
break;
case 4:System.out.println("Ask again later");
break;
case 5:System.out.println(" Better not tell you now");
break;
case 6:System.out.println("Don't count on it");
break;
case 7:System.out.println("My reply is no");
break;
case 8:System.out.println("My sources say no");
break;
case 9:System.out.println("Unlikely");
break;
case 10:System.out.println("Doubtful");
break;
}
}
public static int shake(){
This is another area i think could use a try and catch to check for arithmetic
Random rand = new Random();//using random numbers
int randomInt = rand.nextInt(10 - 1 + 1) + 1;//i used this to get a random number from 1-10
System.out.println(randomInt);
return randomInt;
}
}

Answer 1

Since exceptions are intended primarily for handling errors or other exceptional/unexpected events, a good candidate for such would be your answer() method. Imagine what could go wrong that you might not expect.
For example, what happens when your shake() method returns a value that cannot be handled by your switch statement? Consider a situation in which you increased the range of your random number generator and forgot to add additional cases; or, you didn't dynamically load enough answers from a configuration file.
A simple solution may be to add a default: case that returns some "catch-all" answer (e.g. "I don't know"). However, a better solution would be having the default: case throw an Exception to indicate that your method does not have answers for some rolls.
int roll = shake();
switch ( roll ) {
...
default:
throw new Exception( "No answer for roll: " + roll );
}