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Disregarding the fact that it wont verify although the output matches the condition, somehow i apparently do not display text? what is wrong here. I am certainly printing.

Task: The program reads a pair (a number and string) from the keyboard and displays it on the screen.
New task: The program reads pairs (a number and string) from the keyboard and stores them in a HashMap.
Any empty input signifies the end of data entry.
The numbers can be repeated.
The strings are always unique.
The entered data must not be lost!
The program then displays the contents of the HashMap on the screen.
Each pair on a new line.

Example input:
1 Sam 2 I 1 Am

Example output:
1 Sam 2 I 1 Am

Requirements:

The program must read data from the keyboard.
The program should display text on the screen.
In the main method, declare a HashMap variable and immediately initialize it.
The program should put the pairs read from the keyboard into the HashMap.
The program should display the contents of the HashMap in accordance with the conditions. The key and value are separated by a space. Each value should be on a new line.

package com.codegym.task.task10.task1019; import java.io.*; import java.util.*; /* Functionality is not enough! */ public class Solution { public static void main(String[] args) throws IOException { BufferedReader reader = new BufferedReader(new InputStreamReader(System.in)); HashMap<Integer, String> hash = new HashMap<>(); while(true){ String s = reader.readLine(); String s2 = reader.readLine(); if(s==null){break;} int id = Integer.parseInt(s); String name = s2; hash.put(id,name); if(s2==null){break;} } for(Map.Entry<Integer,String> pair : hash.entrySet()){ int id = pair.getKey(); String name = pair.getValue(); System.out.println(id + " " + name); } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

13 February 2020, 21:55

Few things in this code that need to be corrected to pass: #1 "Any empty input signifies the end of data entry." The first check for empty input is on line 20, after 2 inputs. If the first input is blank then the loop should end #2 "The numbers can be repeated. The strings are always unique." In HashMaps, the keys are unique and the values can be repeated. This means the names have to be the key in this task. #3 Checking for null values does not capture blank inputs such as "". It is a good idea to test for null values, but it is also important to remember that blank values are not equal to null values:

String nullVal = null;
String blankVal = "";
System.out.println(blankVal == null);  // false
System.out.println(blankVal.equals("")); // true
System.out.println(blankVal.equals(nullVal)); //false
System.out.println(nullVal.equals(blankVal));  // null pointer exception thrown

I pointed out what will be displayed, but you can run this code for yourself and see. The last one will throw an exception because nullVal is null and has no valid object for a method to be called upon.