title: Values are always returning null after building object
body: <p>The idea is to print out a simple line saying the book title, author, and price. However, I cannot seem to return any value even after constructing a Book object.</p>
  
  <p>I'm building a Book class, an Author class, and using a Tester to run the program.</p>
  
  <p>Here's what I'm looking at:</p>
  
  <pre><code>package book;
  
  public class Book {
  
      String title;
      Author author;
      double price;
  
      public Book(String title, Author author, double price){}
  
      public Book(){}
  
      public void setbookTitle(String title) {
          this.title = title;
      }
  
      public void setPrice(double price) {
          this.price = price;
      }
  
      public String getTitle() {
          return title;
      }
  
      public Author getAuthor() {
          return author;
      }
  
      public double getPrice() {
          return price;
      }
  
  }
  </code></pre>
  
  <pre><code>package book;
  
  public class Author {
  
      String name;
      String email;
      char gender;
  
      public Author(String name, String email, char gender){
      }
  
      public String getName() {
          return name;
      }
  
      public String getEmail(){
          return email;
      }
  
      public char getGender(){
          return gender;
      }
  
      public void setName(String name) {
          this.name = name;
      }
  
      public void setEmail(String email) {
          this.email = email;
      }
  
      public void setGender(char gender) {
          this.gender = gender;
      }
  
      @Override
      public String toString(){
          return name;
      }
  
  
  
  }
  
  </code></pre>
  
  <pre><code>package book;
  
  public class BookTester {
  
      public static void main(String[] args) {
  
      Author author1 = new Author("Horstmann", "horstmann@gmail.com", 'm');
      Book book1 = new Book("Big Java", author1, 60);
  
      Double number = book1.getPrice();
          System.out.println(number);
  
      System.out.println ("The Book information is: ");
      System.out.println(book1.getTitle() + book1.getAuthor() + book1.getPrice());
  
  
      }
  
  }
  </code></pre>
  
  <p>Any advice would be appreciated!</p>