UsernameRule ensures that password is not containing the username. Consider the following example.

Example

import org.passay.PasswordData;
import org.passay.PasswordValidator;
import org.passay.Rule;
import org.passay.RuleResult;
import org.passay.UsernameRule;

public class PassayExample {
   public static void main(String[] args) {
      //Rule: Password should not contain user-name
      Rule rule = new UsernameRule();
      
      PasswordValidator validator = new PasswordValidator(rule);
      PasswordData password = new PasswordData("microsoft");
      password.setUsername("micro");
      RuleResult result = validator.validate(password);

      if(result.isValid()){
         System.out.println("Password validated.");
      }else{
         System.out.println("Invalid Password: " + validator.getMessages(result));            
      }
   }
}

Output

Invalid Password: [Password contains the user id ''micro''.]