JLabel not Truncating Within JPanel

Question

If I put a JLabel inside of a JPanel with no rigid boundaries, it does not truncate the text when the JPanel is sized to be smaller than the text. Why does this happen? Shouldn't the JPanel realize that there isn't enough room & truncate the text accordingly, regardless of its layout?

As an example, I created a JFrame with a GridLayout with two rows & one column. In that, I placed a JPanel with a FlowLayout on top, & a JPanel with a BoxLayouton the bottom. Each JPanel contains a JLabel.

In short: Why doesn't the JLabel on the top truncate its text?

Images to demonstrate what I mean:

As well, this is the SSCCE to demonstrate the effect:

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

public class TruncationTest1
{
    public static void main(String[] args)
    {
        JFrame f = new JFrame("Truncation Test");
        JPanel panel = new JPanel(); //Default layout, aka FlowLayout
        JLabel label = new JLabel("Try resizing the frame: This will not be truncated for some reason.");
        JLabel label2 = new JLabel("However, this JLabel, on the other hand, will become truncated.");
        f.setLayout(new GridLayout(2,1));
        f.setBackground(Color.BLACK);
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(panel);
            panel.setBackground(Color.WHITE);
            panel.add(label);
        f.add(label2);
            label2.setHorizontalAlignment(JLabel.CENTER);
            label2.setForeground(Color.WHITE);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}

Answer 1

FlowLayout does not resize components inside it. It shows the components with preferred size.

You need to use different layout in place of FlowLayout for proper resizing. For instance you could use BorderLayout with the label at LINE_START or WEST.