step1.rb

include Java

frame = javax.swing.JFrame.new

frame.set_default_close_operation javax.swing.JFrame::EXIT_ON_CLOSE
frame.get_content_pane.add javax.swing.JLabel.new("Hello, World!")

frame.pack
frame.set_visible true

step2.rb

include Java

frame = javax.swing.JFrame.new
frame.get_content_pane.set_layout javax.swing.BoxLayout.new(frame.get_content_pane, javax.swing.BoxLayout::Y_AXIS)

frame.set_default_close_operation javax.swing.JFrame::EXIT_ON_CLOSE

[ javax.swing.JLabel.new("Twitter login:"),
  javax.swing.JTextField.new,
  javax.swing.JLabel.new("Twitter password:"),
  javax.swing.JPasswordField.new,
  javax.swing.JLabel.new("Your tweet:"),
  javax.swing.JTextField.new,
  javax.swing.JButton.new("OK")
].each {|element| frame.get_content_pane.add element}

frame.pack
frame.set_visible true

step3.rb

include Java

class QuickTweetWindow < javax.swing.JFrame
  import javax.swing

  def initialize
    super
    self.get_content_pane.set_layout BoxLayout.new(self.get_content_pane, BoxLayout::Y_AXIS)

    self.set_default_close_operation JFrame::EXIT_ON_CLOSE

    [ JLabel.new("Twitter login:"),
      JTextField.new,
      JLabel.new("Twitter password:"),
      JPasswordField.new,
      JLabel.new("Your tweet:"),
      JTextField.new,
      JButton.new("OK")
    ].each {|element| self.get_content_pane.add element }

    self.pack
    self.set_visible true
  end
end

QuickTweetWindow.new

step4.rb

include Java

class QuickTweetWindow < javax.swing.JFrame
  import javax.swing
  include java.awt.event.ActionListener

  def initialize
    super
    self.get_content_pane.set_layout BoxLayout.new(self.get_content_pane, BoxLayout::Y_AXIS)

    self.set_default_close_operation JFrame::EXIT_ON_CLOSE

    [ JLabel.new("Twitter login:"),
      JTextField.new,
      JLabel.new("Twitter password:"),
      JPasswordField.new,
      JLabel.new("Your tweet:"),
      JTextField.new,
      ok_button = JButton.new("OK")
    ].each {|element| self.get_content_pane.add element }

    self.pack
    self.set_visible true

    ok_button.add_action_listener self
  end

  def actionPerformed(evt); 
    puts "button_clicked!";
  end

end

QuickTweetWindow.new

step5.rb

require 'net/http'
require 'uri'

include Java

class QuickTweetWindow < javax.swing.JFrame
  import javax.swing
  include java.awt.event.ActionListener

  def initialize
    super
    self.get_content_pane.set_layout BoxLayout.new(self.get_content_pane, BoxLayout::Y_AXIS)

    self.set_default_close_operation JFrame::EXIT_ON_CLOSE

    [ JLabel.new("Twitter login:"),
      @login = JTextField.new,
      JLabel.new("Twitter password:"),
      @password = JPasswordField.new,
      JLabel.new("Your tweet:"),
      @tweet = JTextField.new,
      ok_button = JButton.new("OK")
    ].each {|element| self.get_content_pane.add element }

    self.pack
    self.set_visible true

    ok_button.add_action_listener self
  end

  def actionPerformed(evt); 
    send_tweet
  end

  def send_tweet
    url = URI.parse 'http://api.twitter.com/1/statuses/update.xml'
    req = Net::HTTP::Post.new url.path
    req.basic_auth @login.get_text, @password.get_text
    req.set_form_data({'status'=>@tweet.get_text}, ';')
    res = Net::HTTP.new(url.host, url.port).start {|http| http.request req }
  end
end

QuickTweetWindow.new