Why does this swing app hang?

The program hangs after trying to construct another instance of itself when I wait for the reference returned by the constructor to be set.

import java.awt.BorderLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.lang.reflect.InvocationTargetException;
import javax.swing.*;
public class Problem extends JPanel {
    public Problem(boolean wait) {
        frame=new JFrame();
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setLayout(new BorderLayout());
        if(wait) try {
            System.out.println("calling invoke and wait");
            SwingUtilities.invokeAndWait(new Runnable() {
                public void run() {
                    Problem.this.run();
                }
            });
        } catch(InvocationTargetException|InterruptedException e) {
            throw new RuntimeException(e);
        }
        else {
            System.out.println("calling invoke later");
            SwingUtilities.invokeLater(new Runnable() {
                public void run() {
                    Problem.this.run();
                }
            });
        }
    }
    public String title() {
        return "title";
    }
    public void addContent() {
        JButton button=new JButton("click");
        add(button,BorderLayout.CENTER);
        button.addActionListener(new ActionListener() {
            @Override public void actionPerformed(ActionEvent arg0) {
                Runnable runnable=new Runnable() {
                    @Override public void run() {
                        System.out.println("before new "+Thread.currentThread());
                        problem=new Problem(true);
                        System.out.println("after new "+Thread.currentThread());
                    }
                };
                new Thread(runnable).start();
                System.out.println("before first wait "+Thread.currentThread());
                while (problem==null)
                    ;
                System.out.println("before second wait "+Thread.currentThread());
                while (problem.problem==null)
                    ;
                System.out.println("after wait "+Thread.currentThread());
            }
        });
    }
    void run() {
        frame.setTitle(title());
        frame.getContentPane().add(this,BorderLayout.CENTER);
        addContent();
        frame.pack();
        frame.setVisible(true);
    }
    public static void main(String[] args) {
        new Problem(false);
    }
    Problem problem;
    public final JFrame frame;
    private static final long serialVersionUID=1;
}