JScroll don't work in right panel JSplitPane - Swing Java

Question

Can you help me with this problem? I write layout to BitTorrent's client and I don't have any idea why JScroll doesn't work in right panel JSplitPane. More code here: https://github.com/niesuch/bittorrentclient/blob/nie_bittorrentclient/src/Bittorrent.java Thanks in advance.

    /**
     * Initialization information panel
     */
    private void _initInfoPanel() {
        JPanel formPanel = new JPanel();
        formPanel.setBorder(BorderFactory.createTitledBorder("Informations"));

        JPanel form = new JPanel(new GridLayout(0, 2));

        int i = 0;
        for (String formLabel : _formLabels) {
            form.add(new JLabel(formLabel));
            _textFields[i] = new JTextField(10);
            form.add(_textFields[i++]);
        }

        formPanel.add(form);        
        _infoPanel.add(formPanel);        
        _infoPanel.add(new JScrollPane(formPanel), BorderLayout.CENTER);

    }

My minimal example program:

import java.awt.BorderLayout;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JSplitPane;
import javax.swing.JTextField;

public class Test extends JFrame
{
    private final JPanel _downloadsPanel;
    private final JPanel _buttonsPanel;
    private final JPanel _infoPanel;
    private final JTextField[] _textFields;
    private final String[] _formLabels =
    {
        "Name: ", "Size: ", "% downloaded: ", "Status: ",
        "Download: ", "Upload: ", "Time remaining: ", "Pieces: ",
        "Peer data including IP addresses: ", "Speed download from them: ",
        "Speed upload to them: ", "Port using: ", "Port client: "
    };
    private JButton _pauseButton;

    public Test() {
        setTitle("BitTorrent");
        setSize(1024, 768);

        _downloadsPanel = new JPanel();
        _buttonsPanel = new JPanel();
        _infoPanel = new JPanel();
        _textFields = new JTextField[_formLabels.length];

        JSplitPane splitPane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT, _downloadsPanel, _infoPanel);
        splitPane.setResizeWeight(0.7);

        _initInfoPanel();
        _initButtonsPanel();

        getContentPane().setLayout(new BorderLayout());
        getContentPane().add(_buttonsPanel, BorderLayout.SOUTH);
        getContentPane().add(splitPane, BorderLayout.CENTER);        
    }

    private void _initInfoPanel()
    {
        JPanel formPanel = new JPanel();
        formPanel.setBorder(BorderFactory.createTitledBorder("Informations"));

        JPanel form = new JPanel(new GridLayout(0, 2));

        int i = 0;
        for (String formLabel : _formLabels)
        {
            form.add(new JLabel(formLabel));
            _textFields[i] = new JTextField(10);
            form.add(_textFields[i++]);
        }

        formPanel.add(form);        
        _infoPanel.add(formPanel);        
        _infoPanel.add(new JScrollPane(formPanel), BorderLayout.CENTER);

    }


    private void _initButtonsPanel()
    {
        _pauseButton = new JButton("Pause");
        _pauseButton.setEnabled(false);
        _buttonsPanel.add(_pauseButton);

    }

    public static void main(String[] args)
    {
        Test bittorrent = new Test();
        bittorrent.setVisible(true);
    }

}

Answer 1

It's a simple error. You're treating _infoPanel as if it uses BorderLayout, e.g.,

_infoPanel.add(new JScrollPane(formPanel), BorderLayout.CENTER); //!!

But it doesn't and instead uses JPanel's default FlowLayout:

_infoPanel = new JPanel(); 

FlowLayout will display components at their preferredSizes, and will not try to shrink or expand them, and so the JScrollPane will not change its size. So make the obvious change:

_infoPanel = new JPanel(new BorderLayout());