code: public void setUsernames(java.util.Collection<String> usernames) {
          if (usernames == null) {
              this.usernames = null;
              return;
          }
  
          this.usernames = new java.util.ArrayList<String>(usernames);
      }
docs: <p>
  A list of user names.
  </p>
  
  @param usernames
  A list of user names.