我正在处理一个链表项目，需要编写一个ListTester来创建一个链表，然后使用一个对象添加方法（其中包括每个新对象的名称）应打印出整个列表，然后打印头部(first)名称。但是发生的是，它在打印"Exception in thread "main" Actor{ name = EFZASD}"的过程中打印了一半，然后继续打印，并在尝试打印标题时给出了空指针异常。

我试图几次重写add方法，但似乎确实改变了任何东西或使其变得更糟

public class ListTester {
    public static void main(String args[]){

        ActorLinkedList list = new ActorLinkedList();


        list.add(new Actor("ADAD"));
        list.add(new Actor("ERRER"));
        list.add(new Actor("EFZASD"));
        list.add(new Actor("GFSXCZ"));
        list.add(new Actor("WQWR"));


        for (int i = 0; i < list.size(); i++){System.out.println(list.get(i));}

        System.out.println(list.head.getName());


    }

}
public class ActorLinkedList {
    Actor head;
    int count;

    ActorLinkedList(){
       head = null;
    }

    public ActorLinkedList(Actor head, int count) {
        this.head = head;
        this.count = count;
    }

    void add(Actor actor){
        Actor node = new Actor();
        node.name = actor.getName();
        node.next = null;
        node.next = head;

        head = node;
    }

    Actor get(int index){

        Actor current;
        current = head;

        for (int i = 0; i < index; i++){
            current = current.next;
        }
        return current;
    }

    int size(){

        Actor current = head;
        while (current != null) {
            current = current.next;
            count++;
        }
        return count;

    }


}

public class Actor {

    String name;
    Actor next;

    Actor(){
        next = null;
        name = null;
    }

    Actor (String name){
        this.name = name;
        this.next = null;
    }

    String getName() {
        return name;
    }


    void setName (String name){
        this.name = name;
    }

    Actor getNextPtr(){
        return this.next;
    }

    void setNextPtr(Actor next){

        this.next = next;

    }
    @Override
       public String toString(){

           return "\nActor{ name = " + name  + '}';


       }


}

我的结果：

Actor{ name = WQWR}

Actor{ name = GFSXCZ}

Exception in thread "main" Actor{ name = EFZASD}

Actor{ name = ERRER}

Actor{ name = ADAD}

null

java.lang.NullPointerException
    at ActorLinkedList.get(ActorLinkedList.java:29)
    at ListTester.main(ListTester.java:14)

预期产量：

Actor{ name = WQWR}

Actor{ name = GFSXCZ}

{ name = EFZASD}

Actor{ name = ERRER}

Actor{ name = ADAD}

//printed header here