Dealing with Swing Layouts

Question

I have a collection of small panels with fixed size (around 50x50), and a main panel with size around 600x480.
At run time I need to show this collection of panels on my main panel.
Based on your experience, what would be the best layout to show them on my main panel?
I have tried setting up a GridLayout on my main panel, but my small panels always got resized to fill my main panel, no matter how I tried to stablish the number of rows (length % rows == 0? 0 : 1 + len depending on my collection size.
Also tried with a flowlayout, but when I added a JSCrollPanel, instead of adding new rows, my scrollpanel kept adding them on the same line :( I even enforced my scroller to
Is this the correct behaviour? Am I doing something wrong? (I'm sure I do :))
import java.awt.BorderLayout;
import java.awt.Dimension;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.util.List;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import static javax.swing.ScrollPaneConstants.HORIZONTAL_SCROLLBAR_NEVER;
public class JClass extends JFrame{
    private JPanel panel;
    private JScrollPane scroll;
    protected JClass() {
        panel = new JPanel();
        scroll = new JScrollPane(panel);
        scroll.setHorizontalScrollBarPolicy(HORIZONTAL_SCROLLBAR_NEVER);
        JPanel menu  = new JPanel();
        JButton but  = new JButton("show");
        but.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
               display(5);
        BorderLayout layout = new BorderLayout();
        FlowLayout layout2 = new FlowLayout();
        layout2.setAlignment(FlowLayout.LEFT);
        panel.setLayout(layout2);
        menu.add(but);
        this.setPreferredSize(new Dimension(640,480));
        this.setLayout(layout);
        this.add(scroll, BorderLayout.CENTER);
        this.add(menu,BorderLayout.WEST);
        pack();       
    public void display(int n){
        JButton button;      
        for(int i = 0; i < n; i++){
            button = new JButton();
            button.setPreferredSize(new Dimension(30,30));
            this.panel.add(button);
        this.validate();
        this.repaint();     
    public static void main(String args[]) {
        JClass app = new JClass();
        app.setDefaultCloseOperation(EXIT_ON_CLOSE);
        app.setVisible(true);
}

Answer 1

Thanks Camickr.
And just for the sake of it, do you think is there a way to do it with GridLayout? I mean, fixing the number of columns to three, but without resizing the small panels I will be adding. Maybe by fixing the preferredSize of the panel with the gridlayout to the small panels width * 3 + something?
In my previous iteration I tried it but this content panel would always take my maximum space, thus expanding my small panels... :(