How to initialize gui objects in a thread safe manner in java swing?

Question

I'm reading Thinking in Java and the author stresses that main method shouldn't call swing methods. As an example of that practice he presents the following piece of code (available on his webpage):

//: gui/SubmitSwingProgram.java
import javax.swing.*;
import java.util.concurrent.*;

public class SubmitSwingProgram extends JFrame {
  JLabel label;
  public SubmitSwingProgram() {
    super("Hello Swing");
    label = new JLabel("A Label");
    add(label);
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    setSize(300, 100);
    setVisible(true);
  }
  static SubmitSwingProgram ssp;
  public static void main(String[] args) throws Exception {
    SwingUtilities.invokeLater(new Runnable() {
      public void run() { ssp = new SubmitSwingProgram(); }
    });
    TimeUnit.SECONDS.sleep(1);
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        ssp.label.setText("Hey! This is Different!");
      }
    });
  }
} ///:~

The gui object is then created and initialized through invokeLater method making it thread safe. But few pages later the author presents the following code:

//: gui/Button2.java
// Responding to button presses.
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import static net.mindview.util.SwingConsole.*;

public class Button2 extends JFrame {
  private JButton
    b1 = new JButton("Button 1"),
    b2 = new JButton("Button 2");
  private JTextField txt = new JTextField(10);
  class ButtonListener implements ActionListener {
    public void actionPerformed(ActionEvent e) {
      String name = ((JButton)e.getSource()).getText();
      txt.setText(name);
    }
  }
  private ButtonListener bl = new ButtonListener();
  public Button2() {
    b1.addActionListener(bl);
    b2.addActionListener(bl);
    setLayout(new FlowLayout());
    add(b1);
    add(b2);
    add(txt);
  }
  public static void main(String[] args) {
    run(new Button2(), 200, 150);
  }
} ///:~

where SwingConsole is:

//: net/mindview/util/SwingConsole.java
// Tool for running Swing demos from the
// console, both applets and JFrames.
package net.mindview.util;
import javax.swing.*;

public class SwingConsole {
  public static void
  run(final JFrame f, final int width, final int height) {
    SwingUtilities.invokeLater(new Runnable() {
      public void run() {
        f.setTitle(f.getClass().getSimpleName());
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setSize(width, height);
        f.setVisible(true);
      }
    });
  }
} ///:~

So contrary to the previous example an object implementing JFrame is created and initialized within the main method / main thread.

My question is then: (1) Is the second example wrong or is the first one exaggerated? (2) Is it enough that I call swing methods through invokeLater only after the setVisible call and before that statement it is safe to call swing methods within main thread?

Answer 1

The second example is wrong. Swing components must be created and used from the event dispatch thread. See https://docs.oracle.com/javase/tutorial/uiswing/concurrency/initial.html.

Quote from the javadoc:

Calls to an application's main method, or methods in Applet, are not invoked on the event dispatching thread. As such, care must be taken to transfer control to the event dispatching thread when constructing and showing an application or applet.

(emphasis mine)