Help with "incompatible types" error in Java
<p>I can't figure out why it won't compile. And how do I make the error a string?</p>

<pre><code>public class UserID {

  private String firstName; 
  private String lastName;  
  private String userId;  
  private String password;

  public UserID(String first, String last) {
     Random generator = new Random();

     firstName = first;
     lastName = last; 
     userId = first.substring(0, 3) + last.substring(0, 3)
        + generator.nextInt(1) + (generator.nextInt(7) + 3)
        + generator.nextInt(10);
     password = generator.nextInt(10) + generator.nextInt(10)
        + generator.nextInt(10) + generator.nextInt(10)
        + generator.nextInt(10) + generator.nextInt(10);

  } 
}
</code></pre>

<p>Error Message:</p>

<pre><code>UserID.java:36: error: incompatible types
            + generator.nextInt(10);
            ^
  required: String
  found:    int
</code></pre>
