Problem with exceptions and array in Java

Question

I try to create a program in Java that asks user for time (hh:mm:ss format). I have 2 problems:

1) When running the program, as soon as I enter data from the keyboard, the program throws java.lang.NullPointerException.

I am not sure how to fix it. I tried and created global variable for an array but it didn't fix the issue.

2) If I change code.split(":") to code.split(".") program is throwing a MissingColonException loop infinitely.

How can I stop it? I did not include code for exceptions, as I thought the issue is not there.

import java.util.Scanner;

public class CatchExceptionClock {   
    static String [] time;

    public static void main (String[] args) {
        String code = "";
        Scanner scan = new Scanner (System.in); 
        System.out.print ("Please enter time. The input data should have the format hh:mm:ss");
        code = scan.nextLine();

        while (!code.equals ("STOP")) {
             try {     
                 getInput(code);
                 checkHour (time [0]);
                 checkMinutes (time [1]);
                 checkSeconds (time [2]);                     
             } catch (NumberFormatException exception) {
                 System.out.println ("Number is not numeric: " + ". You entered: " + code);
                 System.out.println ("");
             } catch (MissingColonException d) {
                 System.out.println (d.getMessage()+ ". You entered: "+ code); 
                 System.out.println ("0");
             } catch (HourException o) {
                 System.out.println (o.getMessage()+ ". You entered: "+ code); 
                 System.out.println ("");
             } catch (MinutesException e) {
                 System.out.println (e.getMessage()+ ". You entered: "+ code); 
                 System.out.println ("");
             } catch (SecondsException a) {
                 System.out.println (a.getMessage()+ ". You entered: "+ code); 
                 System.out.println ("");
             }

         }
         System.out.print ("Enter  code (STOP to quit): ");
         code = scan.nextLine();
    }




    public static String[] getInput(String code) {
        String [] time = code.split(":");              
        if (time.length ==3)
            return time;
        else 
            throw new MissingColonException("The input is missing a colon.The input data should have the format hh:mm:ss ");    
    }


    public static void checkHour (String time) {
        int hour = Integer.parseInt (time);
        if (hour <0 || hour >24)
            throw new HourException("The hour should be a value between 0 and 24 ");
    }

    public static void checkMinutes (String time) {
        int minutes = Integer.parseInt (time);
        if (minutes <0 || minutes >60)
            throw new MinutesException("Minutes should be a value between 0 and 60 "); 
    }

    public static void checkSeconds (String time) {
         int seconds = Integer.parseInt (time);
         if (seconds <0 || seconds >60)
             throw new SecondsException("Seconds should be a value between 0 and 60 ");
    }   

}

GBlodgett · Accepted Answer · 2019-03-03 23:53:48Z

1

In your getInput method, you create a local array time that shadows the static version. You want:

time = code.split(":");

instead of:

String[] time = code.split(":");

Also none of your methods modify code, so unless the user inputs the stop condition on the first run, the loop will always be infinite. You need to add a

code = scan.nextLine();

at the end of your loop

answered Mar 3, 2019 at 23:53

GBlodgett

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1 Comment

sozidanie Over a year ago

Thank you for great advice! The problem is fixed!

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