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Thread: Some problem with "Main"?

  1. #1
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    Default Some problem with "Main"?

    I'm kind of a coding newb but i managed to make this:
    import java.util.Scanner;
     
    public class ReactionGame {
     
    	public static void main(String[] args) {
     
    		int Time = 0;
    		String s = null;
    		@SuppressWarnings("resource")
    		Scanner NewScanner = new Scanner(System.in);
    		System.out.println("Type K and press enter when STOP appears");
    		Delay(1000);
    		System.out.println("STOP");
    		while (s.equalsIgnoreCase("k")) {
    		String k1 = NewScanner.nextLine();
    		s = k1;
    		Time ++;
    	}
    		System.out.println("Your time was:" + Time);
     
    	}
     
    	private static void Delay(int i) {
    		try {
     
    			  Thread.sleep(100L);
     
    			}
     
    			catch (Exception e) {}  
    	}
    }
    Its supposed to do this:
    Say: when STOP appears enter k and enter!
    then after some time
    STOP
    and then you must type in K+Enter
    Then it will show your Score...
    But it gives this error:

    Type K and press enter when STOP appears
    STOP
    Exception in thread "main" java.lang.NullPointerException
    at ReactionGame.main(ReactionGame.java:14)

    I don't know what i did wrong and even eclipse doesnt give me an answer.

    Kind regards,
    Niels


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: Some problem with "Main"?

    Exception in thread "main" java.lang.NullPointerException
    at ReactionGame.main(ReactionGame.java:14)
    There is a variable with a null value when line 14 is executed. Find the variable with the null value and then backtrack in the code to see why it is null.
    If you don't understand my answer, don't ignore it, ask a question.

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