GUI resizes when calling JLabel.setText()

Question

Case:
I have a GUI with a GridbagLayout.
This is the code for building the GUI.
Important bits:
please note the scrollConsole and adding it way at the end, because that's getting bigger:
NOTE: KwartoButtons are a selfmade class that behaves like a button.
     setSize(600,600);
          Container p1 = getContentPane();
          p1.setLayout(new GridBagLayout());
                    GridBagConstraints c = new GridBagConstraints();
                    c.gridx = 0;
                    c.insets.set(5,8,5,8);
               p1.setBackground(Color.DARK_GRAY);
                      panelVeld = new JPanel(new GridLayout(4,4));
                      panelStukken = new JPanel(new GridLayout(4,4));
                      labelVeld = new JLabel("Speelveld");
                      labelOngespeeld = new JLabel("Ongespeelde Stukken");
                    buttonStop = new JButton("Stop");
                      buttonConsole = new JButton("Hide/Show Console");
                      buttonStart = new JButton("Start");
               textAreaConsole = new JTextArea("");
               buttonPanel = new JPanel(new FlowLayout());
               textAreaConsole.setFont(new Font("Courier",Font.PLAIN, 12));
               aanZet = new JLabel("Niemand aan zet");
                      labelVeld.setForeground(Color.LIGHT_GRAY);
                      labelOngespeeld.setForeground(Color.LIGHT_GRAY);   
                   aanZet.setForeground(Color.LIGHT_GRAY);
                   scrollConsole = new JScrollPane(textAreaConsole,                   JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
                  buttonPanel.add(buttonStart);
                  buttonPanel.add(buttonStop);
                  buttonPanel.setBackground(Color.DARK_GRAY);
                 for(int i=0; i < veld.length; i++)
                      veld[i] = new KwartoButton(null, i, true);
                      veld.addMouseListener(this);
               veld[i].setEnabled(false);
               panelVeld.add(veld[i]);
          Set<Stuk> stukkenSet = spel.getOngespeeld();
          int i=0;
          for(Stuk stuk: stukkenSet)
               stukken[i] = new KwartoButton(stuk, i, false);
               stukken[i].addMouseListener(this);
               stukken[i].setEnabled(false);
               panelStukken.add(stukken[i]);
               i++;
          c.fill = GridBagConstraints.NONE;     
          c.gridx = 0;
               p1.add(labelVeld, c);
          c.gridx = 1;
               p1.add(labelOngespeeld, c);
          c.weightx = 0.5;
          c.weighty = 0.9;
          c.fill = GridBagConstraints.BOTH;     
          c.gridx = 0;
               p1.add(panelVeld, c);
          c.gridx = 1;
               p1.add(panelStukken, c);
          c.fill = GridBagConstraints.VERTICAL;
          c.gridx=0;
          c.gridwidth=2;
          c.weightx=0;
          c.weighty=0;
          p1.add(aanZet,c);
          c.fill = GridBagConstraints.VERTICAL;     
          c.weighty = 0.0;               
          c.gridy=3;
          c.gridwidth=1;
          c.gridx=0;
               p1.add(buttonPanel, c);
          c.gridx=1;
               p1.add(buttonConsole, c);
          c.gridwidth = GridBagConstraints.REMAINDER;     
          c.gridx=0;
          c.gridy=4;
          c.weightx = 1.0;
c.weighty = 0.1;     
               c.fill = GridBagConstraints.BOTH;
          p1.add(scrollConsole, c);          
This is the code I run when the resize happens:
public void setMessage(String s)  {
String message =""
message =s
              if(!message.equals("")) {
                   addToConsole(message);
                   aanZet.setText(message);
public void addToConsole(String s)  {
               // Determine whether the scrollbar is currently at the very bottom position.
               JScrollBar vbar = scrollConsole.getVerticalScrollBar();
               boolean autoScroll = ((vbar.getValue() + vbar.getVisibleAmount()) == vbar.getMaximum());
               // append to the JTextArea (that's wrapped in a JScrollPane named 'scrollPane'
               textAreaConsole.append(s+"\n");
               // now scroll if we were already at the bottom.
               if( autoScroll ) textAreaConsole.setCaretPosition( textAreaConsole.getDocument().getLength() );
     }What my GUI does: When I invoke setMessage(), my scrollConsole grows about one line, until it overpowers the entire GUI (except the buttons).
If I remove the 'auto-scrolldown' functionality of addToConsole, it still resizes, so I reckon that's not the problem.

Answer 1

Here you go.
Thanks in advance.
import java.awt.*;
import javax.swing.*;
* SSCCE Class for my problem.
* Problem: GUI Resizes after calling the update method.
public class TestingClass extends JFrame {
               private JTextArea textAreaConsole;
               private JLabel aanZet;
               private JScrollPane scrollConsole;
     public void update(String s) {          //the problematic method
                   addToConsole(s);                         
                   aanZet.setText(s);
   public void addToConsole(String s) { //adds text to console
               // Determine whether the scrollbar is currently at the very bottom position.
               JScrollBar vbar = scrollConsole.getVerticalScrollBar();
               boolean autoScroll = ((vbar.getValue() + vbar.getVisibleAmount()) == vbar.getMaximum());
               // append to the JTextArea (that's wrapped in a JScrollPane named 'scrollPane'
               textAreaConsole.append(s+"\n");
               // now scroll if we were already at the bottom.
               if( autoScroll ) textAreaConsole.setCaretPosition( textAreaConsole.getDocument().getLength() );
     public TestingClass() {
          super("Test");
          buildGUI();
          setVisible(true);
          update("a");
          update("b");
          update("c");
               update("d");
                    update("e");
                         update("f");
                              update("g");
                                   update("h");
                                        update("i");
                                             update("j");
                                                  update("k");
                                                       update("l");
                                                            update("m");
                                                                 update("n");
                                                                      update("o"); //add more to see more effect, remove to kill problem
     public void buildGUI() { //building the gui
          setSize(600,600);
          Container p1 = getContentPane();
          p1.setLayout(new GridBagLayout());
                    GridBagConstraints c = new GridBagConstraints();
                    c.gridx = 0;
                    c.insets.set(5,8,5,8);
                    JPanel panelVeld = new JPanel(new GridLayout(4,4));
            JPanel panelStukken = new JPanel(new GridLayout(4,4));
                    textAreaConsole = new JTextArea("");
                    textAreaConsole.setFont(new Font("Courier",Font.PLAIN, 12));
                    aanZet = new JLabel("Test!");
                  scrollConsole = new JScrollPane(textAreaConsole, JScrollPane.VERTICAL_SCROLLBAR_ALWAYS, JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
             for(int i=0; i < 16; i++)
                      panelVeld.add(new JButton("x"));
                      panelStukken.add(new JButton("y"));
      c.weightx = 0.5;
      c.weighty = 0.9;
      c.fill = GridBagConstraints.BOTH;     
      c.gridx = 0;
            p1.add(panelVeld, c);
      c.gridx = 1;
               p1.add(panelStukken, c);
             c.fill = GridBagConstraints.VERTICAL;
             c.gridx=0;
             c.gridwidth=2;
             c.weightx=0;
             c.weighty=0;
                  p1.add(aanZet,c);
             c.gridwidth = GridBagConstraints.REMAINDER;     
             c.gridx=0;
             c.gridy=4;
             c.weightx = 1.0;
      c.weighty = 0.1;                    
               c.fill = GridBagConstraints.BOTH;            
                  p1.add(scrollConsole, c);
public static void main(String[] args) { //starting up!
          new TestingClass();
}