Question

Here’s my current code:

import java.lang.String;
import java.io.*;

class InvalidAgeException extends Exception
{
    public InvalidAgeException()
    {
        super("The age you entered is not between 0 and 125");
    }
}

public class questionOne
{
    public static void main(String args[])
    {
        System.out.println("What is your name?");

        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        String name;

        try
        {
            name = br.readLine();
        }
        catch(IOException e)
        {
            System.out.println("Error: " + e);
            System.exit(1);
        }

        System.out.println("Hello " + name + ", how old are you?");

        String i;
        int age;

        try
        {
            i = br.readLine();
            age = Integer.valueOf(i);
        }
        catch(IOException e)
        {
            System.out.println("Error: " + e);
            System.exit(1);
        }
        catch(InvalidAgeException e)
        {
            System.out.println("Error: " + e);
            System.exit(1);
        }
        finally
        {
            System.out.println("No errors found.");
        }
    }
}

The assignment is to write a program that asks for the user’s name and age, and if the age is not between 0 and 125 throw an exception. I’m getting two errors in my code:

questionOne.java:31: variable name might not have been initialized
    System.out.println("Hello " + name + ", how old are you?");
                                  ^
questionOne.java:46: exception InvalidAgeException is never thrown in body of corresponding try statement
    catch(InvalidAgeException e)
    ^
2 errors

I’m not sure how to fix them.

Answer 1

questionOne.java:31: variable name might not have been initialized
    System.out.println("Hello " + name + ", how old are you?");  

It is because variables inside the function needs to be initialized before using it. When you try to use uninitialized variables inside a function, compiler throws an exception.

So, try using this

String name = " ";

---

questionOne.java:46: exception InvalidAgeException is never thrown in body of corresponding try statement
    catch(InvalidAgeException e)  

You have not thrown InvalidAgeException anywhere ( and so the compiler is complaining).

Try this,

  if (age < 0 || age > 125){
    throw new InvalidAgeException("This is an invalid age :" + age);
}