Fluent interface in Java More information here: http://codemonkeyism.com/fluent-interface-and-reflection-for-object-building-in-java/

FluentInterface.java

import java.lang.reflect.*;
import java.beans.*;

public class FluentInterface<T> implements InvocationHandler {
  Object obj;

  public FluentInterface(Object obj) {
    this.obj = obj;
  }

  public static <T> T create(Object object, Class fluentInterfaceClass) {
    FluentInterface handler = new FluentInterface(object);
    @SuppressWarnings("unchecked")
    T fluentInterface = (T) Proxy.newProxyInstance(
       fluentInterfaceClass.getClassLoader(),
        new Class[]{fluentInterfaceClass},
        handler);
    return fluentInterface;
  }

  public Object invoke(Object proxy, Method m, Object[] args) throws Throwable {
    try {
      String name = m.getName();
      if ("create".equals(name)) {
        return obj;
      } else {
        String setter = "set" + name.substring(0, 1).toUpperCase()
          + name.substring(1);
        Statement stmt = new Statement(this.obj, setter, args);
        stmt.execute();
      }
    } catch (Exception e) {
      e.printStackTrace();
    } finally {
    }
    return proxy;
  }
}

Person.java

public class Person {
  private String firstName;
  private String lastName;
  private int age;

  public static PersonFluentInterface with() {
    return FluentInterface.create(
      new Person(), PersonFluentInterface.class);
  }

  public Person() {
  }

  public void setAge(int age){
  	this.age = age;
  }
  public void setFirstName(String firstName){
    this.firstName = firstName;
  }

  public void setLastName(String lastName){
    this.lastName = lastName;
  }

  public String toString(){
  	return "Person("+firstName+", "+lastName+", "+age+")";	
  }

  public static void main(String[] args) {
  Person john = Person.with()
      .firstName("John")
      .lastName("Doe")
      .age(30)
      .create();
  Person bob = Person.with()
  		.age(42)
  		.lastName("Black")
  		.firstName("Bob")
  		.create();

  	System.out.println(john);
  	System.out.println(bob);
  }
}

PersonFluentInterface.java

public interface PersonFluentInterface {
  public PersonFluentInterface firstName(String firstName);
  public PersonFluentInterface lastName(String lastName);
  public PersonFluentInterface age(int age);
  public Person create();
}