Components in JPanel do not change line automatically

Question

import java.awt.BorderLayout;
import java.awt.FlowLayout;
import javax.swing.*;

public class FileCutter
{
    public static void main(String[] args)
    {
        CutterWindow cw = new CutterWindow();
        cw.setResizable(false);
        cw.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        cw.setVisible(true);
    }
}

class CutterWindow extends JFrame
{
    private JTabbedPane tabbedPane = new JTabbedPane();

    public static final int DEFAULT_WIDTH = 470;
    public static final int DEFAULT_HEIGHT = 480;
    public CutterWindow()
    {
        this.setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);
        tabbedPane.add("File Cut",new FileCutPanel());
        this.add(tabbedPane);
    }

}

class FileCutPanel extends JPanel
{   
    private JLabel lblFileName =  new JLabel("File Name:");
    private JTextField txtFileName = new JTextField();
    private JLabel lblFileSize = new JLabel("File Size:");
    private JTextField txtFileSize = new JTextField();
    private JButton btnViewFiles = new JButton("...");

    private JPanel panelSelectOperatingFile = new JPanel();

    public FileCutPanel()
    {   
        panelSelectOperatingFile.setLayout(new FlowLayout());
        panelSelectOperatingFile.add(lblFileName);
        txtFileName.setColumns(20);
        txtFileName.setEditable(false);
        panelSelectOperatingFile.add(txtFileName);
        panelSelectOperatingFile.add(btnViewFiles);
        panelSelectOperatingFile.add(lblFileSize);
        panelSelectOperatingFile.add(txtFileSize);
        txtFileSize.setColumns(20);
        txtFileSize.setEditable(false);

        this.add(panelSelectOperatingFile);
    }
}

the result is that the five component in the panelSelectOperatingFile Panel are in the same line and beyond the width of the window. and i know that the default layout of the JPanel is flowlayout, i expected that the components will be put in the next line when there is no space in the previous line. and i try to figure out the problem, but i can't

Answer 1

Do not use the panelSelectOperatingFile panel. Just add your components to the JPanel you are extending.

You can't nest FlowLayouts. Here is why:

Oracle FlowLayout Tutorial