public LinkedList (Collection c)

public LinkedList(Collection<? extends E> c)

Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.

import java.util.*;

class LinkedListConstructor{
 public static void main(String args[]){
  LinkedList<Integer> myList;
  Collection<Integer> myColl;
  
  myColl = new HashSet<> ();
  
  /* Add Elements to myList */
  myColl.add(10);
  myColl.add(20);
  myColl.add(null);
  
  myList = new LinkedList<> (myColl);
  
  System.out.println("Elements in myList are");
  System.out.println(myList);
 }
}

Output

Elements in myList are
[null, 20, 10]

1. Throws NullPointerException if the specified collection is null

import java.util.*;

class LinkedListConstructorNull{
 public static void main(String args[]){
  LinkedList<Integer> myList;
  Collection<Integer> myColl;
  
  myColl = null;
  
  myList = new LinkedList<> (myColl);
 }
}

Output

Exception in thread "main" java.lang.NullPointerException
        at java.util.LinkedList.addAll(LinkedList.java:406)
        at java.util.LinkedList.addAll(LinkedList.java:385)
        at java.util.LinkedList.<init>(LinkedList.java:117)
        at LinkedListConstructorNull.main(LinkedListConstructorNull.java:10)

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