this is my code and it appears “Exception in thread ”main“ java.lang.NullPointerException” why?

Question

l have an error when running the code this is my code and it appears "Exception in thread "main" java.lang.NullPointerException"

 import com.mongodb.*;
 import java.net.UnknownHostException;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 public class test_3{   
 public static void main(String[] args) {
    try {
        DB myDb ;
        DBCollection myCollection = null;
         Mongo mongo = new Mongo("localhost",27017);
         myDb=mongo.getDB("test_company");   
         myDb.getCollection("login");
         System.out.println((myCollection.find()).toString());   
        } catch (UnknownHostException ex) {
        Logger.getLogger(test_3.class.getName()).log(Level.SEVERE, 

         null,ex);
         }

        }
         }

Answer 1

The null pointer is myCollection , which you've initialized but never assigned a value later on. I assume you meant to assign the return value from myDb.getCollection() ?