Why is this an issue?

As documented in Enumeration 's Javadoc, you should favor the Iterator interface over Enumeration. Iterator offers a similar contract to Enumeration with the addition of a method for removal and shorter method names.

Noncompliant code example

public class MyClass implements Enumeration {  // Noncompliant
  /* ... */
}

Compliant solution

public class MyClass implements Iterator {     // Compliant
  /* ... */
}

Resources

• docs.oracle.com - Enumeration