问在Java中递归删除节点链表

EN

public class LinkedList {
    Node head;
    int index=0;
    Node temp;
    Node prev;
    public LinkedList(Node head){
        this.head=head;
        temp=head;
        prev=null;
    }
    public int length(){
        int counter=0;
        Node n= head.next;
        while(n!=null){
            counter=counter+1;
            n=n.next;
        }
        return counter;
    }
    public void push(Node newNode){
        newNode.next=head;
        head=newNode;
    }
    public void add(Node prevNode, int value){
        if(prevNode==null){
            System.out.println("The given previous node can not be null!");
            return;
        }
        Node newNode= new Node(value,null);
        newNode.next=prevNode.next;
        prevNode.next=newNode;
    }
    public void add(int index, int value){
        length();
        if((index<0)||(index>length())){
            System.out.println("Array out of bound!");
            return;
        }
        if(index==0){
            push(new Node(value,null));
            return;
        }
        Node newNode= new Node(value,null);
        Node prevNode=head;
            for(int i=1;i<index;i++){
            prevNode=prevNode.next;
        }
        newNode.next=prevNode.next;
        prevNode.next=newNode;
    }
    public void delete(){
        head=head.next;
    }
    public void delete(int index){
        if((index<0)||(index>length())){
            System.out.println("Array out of bound!");
            return;
        }
        if(index==0){
            delete();
        return;}
        if(head.next==null||head==null){
            head=null;
        return;}
        if(this.index!=index){
            this.index++;
            prev=temp;
            temp=temp.next;
            delete(index);
        }if(this.index==index){
            prev=temp.next;
        }
    }
    public void search(int value){
        if(head!=null){
        if(value!=head.value){
            head=head.next;
            index=index+1;
            search(value);
        }else if(value==head.value){
            System.out.println("The value \""+value+"\" was found in index: "+index);}}}
    public void display(){
        Node n= head;
        System.out.print("{");
        while(n!=null){
            System.out.print(" ("+n.value+") ");
            n=n.next;
        }System.out.print("}");
        System.out.println("\n------------------------------");
    }
    public static void main(String[]args){
        LinkedList ll= new LinkedList(new Node(2,null));
        ll.push(new Node(5,null));
        ll.push(new Node(6,null));
        ll.push(new Node(13,null));
        ll.push(new Node(1,null));
        ll.display();
        ll.add(ll.head.next,8);
        ll.display();
        ll.add(0, 0);
        ll.display();
        ll.add(6, 4);
        ll.display();
        System.out.println(ll.length());
        ll.search(13);
        ll.delete(2);
        ll.display();
    }
}