title: Creating a new instance of a class from another class
body: <p>So I'm stuck on some homework trying to create an instance of the Employee class from my class called records.</p>
  
  <pre><code>public class Employee implements Comparable&lt;Employee&gt;
  
  {
  /* instance variables */
  private String Name;
  private String employeeNumber;
  
  
  /**
   * Constructor for Employee
   */
  public Employee(String employNum)
  {
     super();
     this.employeeNumber = employNum;             
  }
  </code></pre>
  
  <p>Next I need to create a Record class that will create a HashSet of Employees details, this is where I need help.</p>
  
  <pre><code>public class Records
  {
     private HashSet employeeSet;
  
     public Records()
     {
        Set&lt;Employee&gt; employeeSet = new HashSet&lt;Employee&gt;();
     }
  </code></pre>
  
  <p>Then I want it to have a method for adding a new employee and then putting their records in the set.</p>
  
  <pre><code>   public  enrollEmployee(String num)
     {
        Employee newEmp = new Employee(num);
        employeeSet.add(newEmp);
     }
  }
  </code></pre>
  
  <p>I can't get that last bit to create a new employee, it doesn't come out with an error and it compiles correctly. Just no new employee. 
  *Adding the employeeSet.add(newEmp); caused a compiler warning and that method won't run due to a NullPointerException, probably because the employee isn't actually created.</p>
  
  <p>For more info, when I create an employee the name should come out as "null" if only an employee number is entered but I still need to store that information.</p>
  
  <p>Edited to update information. There is more detail for the Employee class which I have left out, I'm only supposed to be creating the Records class.</p>
  
  <p>Last update, thank you for the help. After reading the replies this is what I got to work for me.</p>
  
  <pre><code>   public class Records
  {
     private Set&lt;Employee&gt; employeeSet = new HashSet&lt;Employee&gt;();
  
     public Records()
     {
  
     }
  
     public void enrollEmployee(String num)
     {
        Employee newEmp = new Employee(num);
        employeeSet.add(newEmp);
     }
  }
  </code></pre>