A few exceptions being thrown

[wdh321]

I have a few issues, i have a class Registry which is a linked list of Students. I also have a class Registry tester to test the methods.
Both classes have no errors however on line 13, net beans is telling me to "Assign return value to New Variable".

import java.util.LinkedList;
public class Registry 
{
    LinkedList<Student> StudentList;
    
    public Registry()
    {
      LinkedList<Student> StudentList = new LinkedList<Student>();  
    }
    
    public void addStudent(Student aStudent )
    {
        StudentList.add(aStudent);
    }

The main problem is whilst trying to run the Registry Tester. When i run it i get this exception.
Exception in thread "main" java.lang.NullPointerException
at Registry.addStudent(Registry.java:13)
at RegistryTester.main(RegistryTester.java:6)
Java Result: 1

I have searched this but cant find an answer, i assume its related to line 13 in the Registry class?

public class RegistryTester
{
    public static void main(String[] args)
    {
        Registry aRegistry = new Registry();
        aRegistry.addStudent(new Student("steve","davies",1006));
        System.out.println("Testing Registry Class");
        System.out.println("**********************\n");
        
        System.out.println("Test 1: toString() method");
        System.out.println("*************************");
        
    }
    
}

[jlczuk]

Withdrawn, I was incorrect.

[KevinWorkman]

In your Registry constructor, you create a new variable named StudentList (variables should start with a lower-case letter, by the way). That variable hides the class variable with the same name, which remains unchanged. You then try to use the class variable, but since you never assigned anything to it, you get an NPE.

[wdh321]

I see what your saying, im a bit confused as to what to change to get it working correctly. Its my first time using linked lists so i wasnt to sure how to initiate it in public Registry

[KevinWorkman]

This doesn't really have anything to do with LinkedLists. For example:

public class Test{
   String testString;

   public Test(){
      String testString = "test String";
   }

   public void printString(){
      System.out.println(testString);
   }

}

[wdh321]

Sorted :) thanks for steering me in the right direction.