Efecto de explosión al abrir un JPanel

import java.awt.Dimension;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import javax.swing.JPanel;
/**
 * @web https://www.jc-mouse.net/
 * @author Mouse
 */
public class explode {

    private ScheduledExecutorService scheduler = Executors.newSingleThreadScheduledExecutor();    
    private Dimension d;
    private int count = 0;
    //
    private JPanel container;
    private JPanel content;
    //coordenadas del JPanel contenido
    private int px=0;
    private int py=0;
    //
    private int ancho_min = 10;
    private int alto_min = 10;
    private int velocidad = 20;//en milisegundos

    /**
 * Constructor de clase
 */
    public explode( JPanel container , JPanel content )
    {
        this.container = container;
        this.content = content;        
        this.container.removeAll();

        d = new Dimension( 10 ,10 );
        this.content.setSize( d );//tamaño inicial

        //coordenadas iniciales
        px = this.container.getSize().width/2-this.ancho_min/2;
        py = this.container.getSize().height/2-this.alto_min/2;        
        content.setLocation( px, py );
        content.setVisible(true);

        //se agrega al contenedor el JPanel contenido
        this.container.add( content );
        count = 10;
    }

    /**
 * Metodo para ejecutar el efecto EXPLODE
 */
    public void play()
    {       
        scheduler = Executors.newSingleThreadScheduledExecutor();
        scheduler.scheduleAtFixedRate( 
            new Runnable() 
            {

                @Override
                public void run() {                     
                    //nuevo tamaño 
                    d = new Dimension( container.getSize().width * count/100 , container.getSize().height * count/100 );
                    count = count + 10;
                    //se recalcula la posicion mientras el jpanel crece
                    px = container.getSize().width/2-d.width/2;
                    py = container.getSize().height/2-d.height/2;        
                    content.setLocation( px, py );

                   if( count > 100 ) 
                   {                       
                       close();                       
                   }
                   content.setSize( d );
                   container.updateUI();                        
                }
              }, 100, velocidad , TimeUnit.MILLISECONDS );

    }

    /**
 * Metodo para terminar el efecto explode
 */
    public void close() {
        scheduler.shutdownNow();
    }

}//--> fin clase

01 public class gui extends javax.swing.JFrame {
02 
03     panel_A panel_a = new panel_A();
04     panel_B panel_b = new panel_B();

01     private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
02         new explode( CONTAINER , panel_a ).play();
03     }                                        
04 
05     private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
06         new explode( CONTAINER , panel_b ).play();
07     }