JScrollPane in GridBagLayout is either at minimum or contents' size

This is the problem:

I try to use components that are contained within JScrollPanes in a
design that uses GridBagLayout as a layout-manager. But if the
component's size exceeds the space allotted to it by the layout-
manager, it is displayed at minimum size. Otherwise, it is displayed
at full size without any scrollbars needed.

The code below replicates the problem. Note that setting the layout-
manager to BorderLayout, putting the JScrollPane in the centre and
label2 in the east solves the problem - but this isn't an option in
the original program.

So, I need a JScrollBar that occupies all the space allotted by the
layout-manager. In the example given below, that would be all the
space available in the frame after placing label2.

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

public class ScrollPaneResize extends JFrame{
    ScrollPaneResize(){
        this.setSize(100, 100);
        this.setDefaultCloseOperation(ScrollPaneResize.EXIT_ON_CLOSE);

        getContentPane().setLayout(new GridBagLayout());
        GridBagConstraints constraints = new GridBagConstraints();
        constraints.gridx = 0;
        constraints.gridy = 0;

        JLabel label = new JLabel("some incredibly long text is put here,
that makes the label bigger than the frame's size");
        JLabel label2 = new JLabel("shorttext");

        JPanel panel = new JPanel();
        panel.add(label);

        JScrollPane scrollpane = new JScrollPane(panel);

        this.getContentPane().add(scrollpane, constraints);
        constraints.gridx = 1;
        this.getContentPane().add(label2, constraints);

        this.setVisible(true);
    }

    public static void main(String[] args){
        ScrollPaneResize spc = new ScrollPaneResize();
    }
}