Java: collection移除空元素

package tt;

import java.util.Collections;
import java.util.LinkedList;
import java.util.List;

public class Test3 {
    public static void main(String[] args) {
        List<String> myList=new LinkedList<String>();
        myList.add("tju");
        myList.add("ttt");
        myList.add(null);
        myList.add("hi");
        System.out.println(myList.size());
        myList.removeAll(Collections.singleton(null));
        System.out.println(myList.size());
    }
}