But I remember オブジェクト指向 ref: http://qiita.com/items/5cbba25f1d4d7c8953e5

file10.txt

class FullnameInJapan() extends Fullname {
  override def get(firstname: String, lastname: String) = lastname + " " + firstname
}

file11.txt

val user1 = new User(1, "源次", "富樫", new FullnameInJapan)

file2.txt

val user = new User(1, "源次", "富樫")
user.firstname

file4.txt

$ scala User1.scala
User1.scala:6: error: value id in class User cannot be accessed in this.User
println(user.id)
             ^
one error found

file6.txt

$ scala User2.scala
富樫 源次
鯛雄 松尾

file7.txt

class User(val id: Long, val firstname: String, val lastname: String, val fullname:Fullname = new Fullname) {
  def getFullname() = this.fullname.get(firstname, lastname)
}

file8.txt

val user2 = new User(2, "鯛雄", "松尾")

file9.txt

class Fullname() {
  def get(firstname: String, lastname: String) = firstname + " " + lastname
}

User.java

public class User {

    private final long id;

    private final String firstname;

    private final String lastname;

    public User(long id, String firstname, String lastname) {
        this.id = id;
        this.firstname = firstname;
        this.lastname = lastname;
    }

    public long getId() {
        return id;
    }

    public String getFirstname() {
        return firstname;
    }

    public String getLastname() {
        return lastname;
    }

    public String getFullname() {
        return this.firstname + " " + this.lastname;
    }
}

User.scala

class User(val id: Long, val firstname: String, val lastname: String) {
  def getFullname() = this.firstname + " " +  this.lastname
}

User1.scala

class User(private val id: Long, private val firstname: String, private val lastname: String) {
  def getFullname() = this.firstname + " " +  this.lastname
}

val user = new User(1, "源次", "富樫")
println(user.id)

User2.scala

class User(val id: Long, val firstname: String, val lastname: String, val fullname:Fullname = new Fullname) {
  def getFullname() = this.fullname.get(firstname, lastname)
}

class Fullname() {
  def get(firstname: String, lastname: String) = firstname + " " + lastname
}

class FullnameInJapan() extends Fullname {
  override def get(firstname: String, lastname: String) = lastname + " " + firstname
}

val user1 = new User(1, "源次", "富樫", new FullnameInJapan)
println(user1.getFullname())

val user2 = new User(2, "鯛雄", "松尾")
println(user2.getFullname())