Java - Delete odd nodes of the Circular Singly Linked List

void deleteOddNodes() {
  //1. if head is the only element element in 
  //   list make the head as null  
  if(this.head != null && this.head.next == this.head) {
    this.head = null;
  } else if(this.head != null) {

    //2. if the list contains more than one element
    //   delete the head and adjust the link of
    //   last element with the new head       
    Node temp = this.head;
    while(temp.next != this.head) {
      temp = temp.next;
    }
    temp.next = head.next;
    this.head = null;
    this.head = temp.next;

    //3. create evenNode node - pointing to head
    //   oddNode node - pointing to next of head
    //   temp node - to store last even node
    if(this.head != null && this.head.next != this.head) {

      Node evenNode = this.head;
      Node oddNode = this.head.next; 
      while(true) {
        
        //4. delete odd node and update evenNode and 
        //   oddNode to next set of odd-even nodes update
        //   temp node to latest evenNode node continue
        //   the process till any of the node reaches head
        temp = evenNode;
        evenNode.next = oddNode.next;
        oddNode = null;
        evenNode = evenNode.next;
        oddNode = evenNode.next;
        if(evenNode == this.head || oddNode == this.head)
          break;
      }
      
      //5. if evenNode reaches head, make next of temp
      //   as head else make next of evenNode as head
      if(evenNode == this.head)
        temp.next = this.head;
      else
        evenNode.next = this.head;
    }
  } 
}

//node structure
class Node {
    int data;
    Node next;
};

class LinkedList {
  Node head;

  LinkedList(){
    head = null;
  }

  //Add new element at the end of the list
  void push_back(int newElement) {
    Node newNode = new Node();
    newNode.data = newElement;
    newNode.next = null; 
    if(head == null) {
      head = newNode;
      newNode.next = head;
    } else {
      Node temp = new Node();
      temp = head;
      while(temp.next != head)
        temp = temp.next;
      temp.next = newNode;
      newNode.next = head;
    }    
  }

  //delete odd nodes of the list
  void deleteOddNodes() {
    if(this.head != null && this.head.next == this.head) {
      this.head = null;
    } else if(this.head != null) {    
      Node temp = this.head;
      while(temp.next != this.head) {
        temp = temp.next;
      }
      temp.next = head.next;
      this.head = null;
      this.head = temp.next;

      if(this.head != null && this.head.next != this.head) {

        Node evenNode = this.head;
        Node oddNode = this.head.next; 
        while(true) {
          temp = evenNode;
          evenNode.next = oddNode.next;
          oddNode = null;
          evenNode = evenNode.next;
          oddNode = evenNode.next;
          if(evenNode == this.head || oddNode == this.head)
            break;
        }
        
        if(evenNode == this.head)
          temp.next = this.head;
        else
          evenNode.next = this.head;
      }
    } 
  }   

  //display the content of the list
  void PrintList() {
    Node temp = new Node();
    temp = this.head;
    if(temp != null) {
      System.out.print("The list contains: ");
      while(true) {
        System.out.print(temp.data + " ");
        temp = temp.next;
        if(temp == this.head)
          break;
      }
      System.out.println();
    } else {
      System.out.println("The list is empty.");
    }
  }     
};

// test the code 
public class Implementation {
  public static void main(String[] args) {
    LinkedList MyList = new LinkedList();

    //Add five elements in the list.
    MyList.push_back(10);
    MyList.push_back(20);
    MyList.push_back(30);
    MyList.push_back(40);
    MyList.push_back(50);

    //Display the content of the list.
    MyList.PrintList();

    //delete odd nodes of the list
    MyList.deleteOddNodes();
 
    System.out.println("After deleting odd nodes:");
    //Display the content of the list.
    MyList.PrintList();
  }
}