Difference between Value Object pattern and Data Transfer pattern

Question

In which scenario can I use those design patterns in n-tier architecture?

Answer 1

Value Object and Data Transfer Object are design pattern.

• Value Object : Use when need to measure the objects' equality based on the objects' value.

Real world example is java.time.LocalDate

public class HeroStat {

   // Stats for a hero

   private final int strength;
   private final int intelligence;
   private final int luck;

   // All constructors must be private.
   private HeroStat(int strength, int intelligence, int luck) {
    this.strength = strength;
    this.intelligence = intelligence;
    this.luck = luck;
   }

  // Static factory method to create new instances.
  public static HeroStat valueOf(int strength, int intelligence, int luck) {
    return new HeroStat(strength, intelligence, luck);
  }

  public int getStrength() {
     return strength;
  }

  public int getIntelligence() {
     return intelligence;
  }

  public int getLuck() {
     return luck;
  }

  /*
   * Recommended to provide a static factory method capable of creating an instance 
       from the formal
   * string representation declared like this. public static HeroStat parse(String 
     string) {}
   */

  // toString, hashCode, equals

  @Override
  public String toString() {
      return "HeroStat [strength=" + strength + ", intelligence=" + intelligence
    + ", luck=" + luck + "]";
  }

  @Override
  public int hashCode() {
     final int prime = 31;
     int result = 1;
     result = prime * result + intelligence;
     result = prime * result + luck;
     result = prime * result + strength;
     return result;
  }

  @Override
  public boolean equals(Object obj) {
       if (this == obj) {
          return true;
        }
       if (obj == null) {
          return false;
       }
       if (getClass() != obj.getClass()) {
          return false;
       }
       HeroStat other = (HeroStat) obj;
       if (intelligence != other.intelligence) {
          return false;
       }
       if (luck != other.luck) {
          return false;
       }
       if (strength != other.strength) {
          return false;
       }
          return true;
    }
    // The clone() method should not be public. Just don't override it.
  }

- Data Transfer Object : Pass data with multiple attributes in one shot from client to server, to avoid multiple calls to remote server.

  public class CustomerDto {
       private final String id;
       private final String firstName;
       private final String lastName;

       /**
        * @param id        customer id
        * @param firstName customer first name
        * @param lastName  customer last name
        */
        public CustomerDto(String id, String firstName, String lastName) {
           this.id = id;
           this.firstName = firstName;
           this.lastName = lastName;
        }

        public String getId() {
           return id;
        }

        public String getFirstName() {
           return firstName;
        }

        public String getLastName() {
           return lastName;
        }
     }