[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.