import java.util.ArrayList;
import java.util.List;

import org.passay.CharacterRule;
import org.passay.EnglishCharacterData;
import org.passay.LengthRule;
import org.passay.PasswordData;
import org.passay.PasswordValidator;
import org.passay.Rule;
import org.passay.RuleResult;
import org.passay.WhitespaceRule;

public class PassayExample {
   public static void main(String[] args) {
        
      List rules = new ArrayList<>();        
      //Rule 1: Password length should be in between 
      //8 and 16 characters
      rules.add(new LengthRule(8, 16));        
      //Rule 2: No whitespace allowed
      rules.add(new WhitespaceRule());        
      //Rule 3.a: At least one Upper-case character
      rules.add(new CharacterRule(EnglishCharacterData.UpperCase, 1));        
      //Rule 3.b: At least one Lower-case character
      rules.add(new CharacterRule(EnglishCharacterData.LowerCase, 1));        
      //Rule 3.c: At least one digit
      rules.add(new CharacterRule(EnglishCharacterData.Digit, 1));        
      //Rule 3.d: At least one special character
      rules.add(new CharacterRule(EnglishCharacterData.Special, 1));
        
      PasswordValidator validator = new PasswordValidator(rules);        
      PasswordData password = new PasswordData("Microsoft@123");        
      RuleResult result = validator.validate(password);
        
      if(result.isValid()){
         System.out.println("Password validated.");
      }else{
         System.out.println("Invalid Password: " + validator.getMessages(result));            
      }
   }
}

Password validated.