!629 // standard function adder
!592 // auto-import
!614 // actionListener {
!619 // standard classes (LetterLayout, CenteredLine)

import java.awt.*;
import java.awt.event.*;
import java.util.List;

public class main {
  public static void main(String[] args) {
    JFrame frame = new JFrame("A JavaX Frame");
    
[...]
    
    frame.add(panel);
    frame.setBounds(100, 100, 500, 400);
    frame.setVisible(true);
    exitOnFrameClose(frame);
  }
}

Began life as a copy of #1000288