Treets - ClassCastException Error

import java.util.Arrays;
import java.util.Date;

import com.teamtreehouse.Treet;
import com.teamtreehouse.Treets;

public class Example{

  public static void main(String[] args){
//    Treet treet = new Treet(
//      "craigsdennis",
//      "Want to be famous? Simply tweet about Java and use " +
//        "the hashtag #treet. I'll use your tweet in a new " +
//        "@treehouse course about data structures.",
//      new Date(1421849732000L)
//    );
//    Treet secondTreet = new Treet(
//      "journeytocode",
//      "@treehouse makes learning Java sooooo fun! #treet",
//      new Date(1421878767000L)
//    );
//    System.out.printf("This is a new Treet: %s %n", treet);
//    System.out.println("The words are:");
//    for (String word : treet.getWords()){
//      System.out.println(word);
//    }
//    
//    Treet[] treets = {treet, secondTreet};
//    Arrays.sort(treets);
//    for(Treet exampleTreet : treets){
//      System.out.println(exampleTreet);
//    }
//    Treets.save(treets);
    Treet[] reloadedTreets = Treets.load();
    for(Treet reloaded : reloadedTreets){
      System.out.println(reloaded);
    }
  }
}

package com.teamtreehouse;

import java.io.Serializable;
import java.util.Date;

public class Treet implements Comparable, Serializable{
  //private boolean mBreakIt = true;
  private String mAuthor;
  private String mDescription;
  private Date mCreationDate;

  public Treet(String author, String description, Date creationDate){
    mAuthor = author;
    mDescription = description;
    mCreationDate = creationDate;
  }

  @Override
  public String toString(){
    return String.format("Treet: \"%s\" by %s on %s",
                         mDescription, mAuthor, mCreationDate);
  }

  @Override
  public int compareTo(Object obj){
    Treet other = (Treet) obj;
    if (equals(other)){
      return 0;
    }
    int dateCmp = mCreationDate.compareTo(other.mCreationDate);
    if (dateCmp == 0){
      return mDescription.compareTo(other.mDescription);
    }
    return dateCmp;
  }

  public String getAuthor(){
    return mAuthor;
  }

  public String getDescription(){
    return mDescription;
  }

  public Date getCreationDate(){
    return mCreationDate;
  }

  public String[] getWords(){
    return mDescription.toLowerCase().split("[^\\w#@']+");
  }
}

package com.teamtreehouse;

import java.io.*;

public class Treets{

  public static void save(Treet[] treets){
     try(
      FileOutputStream fos = new FileOutputStream("treets.ser");
      ObjectOutputStream oos = new ObjectOutputStream(fos);
     ){
      oos.writeObject("treets");
     } catch(IOException ioe){
      System.out.println("Problem saving Treets");
      ioe.printStackTrace();
     }
  }

  public static Treet[] load() {
    Treet[] treets = new Treet[0];
    try (
      FileInputStream fis = new FileInputStream("treets.ser");
      ObjectInputStream ois = new ObjectInputStream(fis);
    ) {
      treets = (Treet[]) ois.readObject();
    } catch(IOException ioe) {
      System.out.println("Error reading file");
      ioe.printStackTrace();
    } catch(ClassNotFoundException cnfe) {
      System.out.println("Error loading treets");
      cnfe.printStackTrace();
    }
    return treets;
  }
}