title: What happens if I don't implement Serializable when using Hashmap
body: <p>What would happen if I don't include "implements Serializable?"</p>
  
  <pre><code>public class Student implements Serializable {
      private String studentNumber;
      private String firstName;
      private String lastName;
      private ArrayList&lt;Exam&gt; exams;
  }
  </code></pre>