Getting nullpointerException. I've re-read the code several times even got rid of return null but nothing seems to be working. Pls help!!! Thanks

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package com.codegym.task.task07.task0701;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/*
Maximum in an array

*/

public class Solution {
    public static void main(String[] args) throws Exception {
        int[] array = initializeArray();
        int max = max(array);
        System.out.println(max);
    }

    public static int[] initializeArray() throws IOException {
        // Create and populate the array
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        int[] x = new int[20];

        for(int i =0; i < x.length; i++){
            x[i] = Integer.parseInt(reader.readLine());
        }


        return null;
    }

    public static int max(int[] array) {
        // Find the maximum
        int maxi = array[0];

        for(int i = 0; i < array.length; i++){
            if (array[i] > maxi){
                maxi = array[i];
            }
        }
        return 0;
    }
}

package com.codegym.task.task07.task0701; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; /* Maximum in an array */ public class Solution { public static void main(String[] args) throws Exception { int[] array = initializeArray(); int max = max(array); System.out.println(max); } public static int[] initializeArray() throws IOException { // Create and populate the array BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); int[] x = new int[20]; for(int i =0; i < x.length; i++){ x[i] = Integer.parseInt(reader.readLine()); } return null; } public static int max(int[] array) { // Find the maximum int maxi = array[0]; for(int i = 0; i < array.length; i++){ if (array[i] > maxi){ maxi = array[i]; } } return 0; } }

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Thomas

Level 41 , Bayreuth, Germany

22 July 2022, 12:34

initializeArray() returns null instead of the array you created there. That null is assigned to array in line 14. First time you 'use' that array will lead to a NullPointerException (inside the max method). Here you have a similar problem and return 0 instead of the max value you calculated. You could improve your algorithm a little bit if you do not start the loop from 0 but from 1 (the first array element you already evaluated when assigning a value to maxi).

Anonymous #10798360

Level 8 , Woking, United Kingdom

23 July 2022, 15:36

I'm really sorry but I still don't understand. I've fixed the algorithm best as I could but I keep getting the same nullPointerException.

package com.codegym.task.task07.task0701;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

/*
Maximum in an array

*/

public class Solution {
    public static void main(String[] args) throws Exception {
        int[] array = initializeArray();
        int max = max(array);
        System.out.println(max);
    }

    public static int[] initializeArray() throws IOException {
        // Create and populate the array
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));

        int[] x = new int[20];
        return null;
    }

    public static int max(int[] array) {
        // Find the maximum
        int maximum = array[0];
        for(int i = 1; i < array.length; i++){
            if(array[i] > maximum){
                maximum = array[i];
            }
        }
        return maximum;
    }
}

Thomas

Level 41 , Bayreuth, Germany

23 July 2022, 16:48

solution

In line 24 you return null instead of (I assume you wanted to do that instead) x. In your original code you had a loop to read values and populate the array. That you need again. And, as said, you have to return the reference to that array and not null. Otherwise in line 14 you assign that null to array, call max with null as argument and in line 30 when you try to access the length field of array the code throws the exception (null does not have a length field). Line 30 and 35 you fixed ;) excellent

Anonymous #10798360

Level 8 , Woking, United Kingdom

24 July 2022, 07:35

Thanks! I fixed it. It works now.