Need help on Exception

[Deon]

Output i must get







When i type in the Letters i get "Please enter positive integer values only" instead of "Please enter in numbers, not letters"

i just can't slove it

PHP Code:

import javax.swing.JOptionPane;
import java.util.InputMismatchException;

public class Chapter8Q2
{
   public static void main ( String[] args ) {
    
    int age ;
    String message1 = "Please enter your age in years" + "\n";
    String message3 = "Please enter positive integer values only"+ "\n";
    String message4 = "Please enter in numbers, not letter"+ "\n";
    String temp ,outputMessage ;

try{

    temp = JOptionPane.showInputDialog(message1);
    age = Integer.parseInt(temp);
    
    if( age < 0)
        throw new IllegalArgumentException();
    outputMessage = "Your age is "+ age + " years"+ "\n";
    JOptionPane.showMessageDialog(null, outputMessage);
    
}//end try


catch( InputMismatchException e)    //non number
{
    JOptionPane.showMessageDialog(null, message4);
}//end catch


catch( IllegalArgumentException e)    //negative number
{
    JOptionPane.showMessageDialog(null, message3);

}//end catch


System.exit(0);

}//main
}//class 


[Eranga]

I don't have Java IDE on this machine now. Can you just change two catch statements and see it give any exception there. I'm just seeking on it.

[CaptainMorgan]

Your input is related to Integer and its method(s), namely parseInt(). And you want to catch the NumberFormatException because this is thrown if the String cannot be parsed into an int.

Code:

import javax.swing.JOptionPane; 

public class Chapter8Q2 
{ 
   public static void main ( String[] args ) { 
    Integer age = new Integer(0); // initialization
    int year; 
    String message1 = "Please enter your age in years" + "\n"; 
    String message3 = "Please enter positive integer values only"+ "\n"; 
    String message4 = "Please enter in numbers, not letter"+ "\n"; 
    String temp ,outputMessage ; 

try{ 

    temp = JOptionPane.showInputDialog(message1);
 
    year= age.parseInt(temp); 
     
    if( year< 0) 
        throw new IllegalArgumentException(); 

    outputMessage = "Your age is "+ year+ " years"+ "\n"; 
    JOptionPane.showMessageDialog(null, outputMessage); 
     
}//end try 


catch( NumberFormatException e)  // can't parse the String into an int
{
        JOptionPane.showMessageDialog(null, message4);
}
 

catch( IllegalArgumentException e)    //negative number 
{ 
    JOptionPane.showMessageDialog(null, message3); 

}//end catch 


System.exit(0); 

}//main 
}//class  

Hope this helps.

[Deon]

wow! it's work thx again! Captain Morgan

[tim]

Hello Deon

If you do not know what exceptions or errors to catch then use this:

Code:

try{
    int a = 1, b = 0;
    int c = a / b;
} catch (Throwable e) {
    System.out.println(e.getClass().getName());
}

This will tell you what exception was caught.

I'm going to install my JDK now, so please, mind the bugs.

[Deon]

thx alot tim!