import java.util.*;
import java.util.function.Consumer;

class Mailer {
  public Mailer from(String addr) { System.out.println("from"); return this; }
  public Mailer to(String addr) { System.out.println("to"); return this; }
  public Mailer sub(String line) { System.out.println("sub"); return this; }
  public Mailer body(String msg) { System.out.println("body"); return this; }
  public static void send(Consumer<Mailer> block) { 
    Mailer mailer = new Mailer();
    block.accept(mailer);
    System.out.println("sending..."); 
  }
}

public class Sample { 
  public static void main(String[] args) {
    Mailer.send(mailer -> 
      mailer.from("builder@agiledeveloper.com")
            .to("venkats@agiledeveloper.com")
            .sub("Your code sucks")
            .body("......"));
  }
}