ContentPane wont be size i want it to be?

Question

Hi i am having trouble with this program i need to make for an exercise, i just need to create the shape of a calender using GridBagLayout. I know that the code i have works because i had it just in a main method before, but now i am trying to make it into an object so i can use it later. the issue is that no matter what the panels that i create are tiny, no matter what values i input for size. i have posted my class and testclass below, let me know if you have any questions
public class TCalander{
    private int calWidth;
    private int calHeight;
    private JPanel pane = new JPanel();
    public TCalander() {
        //blank
    public TCalander(int c_W, int c_H) {
        calWidth = c_W;
        calHeight = c_H;
        pane.setPreferredSize(new Dimension(c_W, c_H));
        createComponents();
    private void createComponents() {
        //create JPanel to be used and make the border black for ease
        JPanel panels[] = new JPanel[50];
        for(int i = 0; i < panels.length; i++) {
            panels[i] = new JPanel();
            panels.setBorder(BorderFactory.createLineBorder(Color.black));
//set the passed through container's layout
pane.setLayout(new GridBagLayout());
//create a set of constraints
GridBagConstraints c = new GridBagConstraints();
//add the top bar
panels[0].setPreferredSize(new Dimension(calWidth, (int)(0.1 * calHeight)));
c.gridx = 0;
c.gridy = 0;
c.gridwidth = 7;
c.gridheight = 1;
c.weighty = (int)(0.1 * 0.05 * calHeight);//5% of top section
pane.add(panels[0], c);
//reset weight
c.weighty = 0;
//add the day labels
for(int i = 0; i < 7; i++) {
panels[i+1].setPreferredSize(new Dimension(100, (int)(0.0358 * calHeight)));
c.gridx = i;
c.gridy = 1;
c.gridwidth = 1;
c.gridheight = 1;
pane.add(panels[i+1], c);
//add the day boxes
int panelAt = 8;
for(int row = 0; row < 6; row++) {//each row
for(int col = 0; col < 7; col++) {//each column
int sum = (int)(0.1 * calHeight) +
(int)(0.0358 * calHeight) +
(int)(0.1432 * calHeight) +
(int)(0.1432 * calHeight) +
(int)(0.1432 * calHeight) +
(int)(0.1432 * calHeight) +
(int)(0.1432 * calHeight);
panels[panelAt].setPreferredSize(new Dimension(100, (calHeight - sum)));
c.gridx = col;
c.gridy = row + 2;
c.gridwidth = 1;
c.gridheight = 1;
pane.add(panels[panelAt], c);
panelAt++;
public JPanel getPanel() {
return pane;
test class:public static void main(String[] args) {
JFrame frame = new JFrame("GridBagLayoutDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(new Dimension(500, 500));
TCalander cal = new TCalander(500, 500);
frame.setContentPane(cal.getPanel());
System.out.println(frame.getContentPane().getPreferredSize());//for debuging
System.out.println(frame.getContentPane().getSize());//for debugging
frame.setVisible(true);
the output is:
java.awt.Dimension[width=500,height=500]
java.awt.Dimension[width=0,height=0]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       

Answer 1

I'll reiterate what camickr has said. GridBagLayout is the most difficult one. I don't know why you fill compelled to use it.
import javax.swing.*;
import java.awt.*;
public class TCalander{
    private JPanel pane = new JPanel();
    public TCalander() {
        //blank
    public TCalander(int c_W, int c_H) {
        pane.setPreferredSize(new Dimension(c_W, c_H));
        createComponents();
    private void createComponents() {
        //create JPanel to be used and make the border black for ease
        JPanel panels[] = new JPanel[50];
        for(int i = 0; i < panels.length; i++) {
            panels[i] = new JPanel();
            panels.setBorder(BorderFactory.createLineBorder(Color.black));
//set the passed through container's layout
pane.setLayout(new GridBagLayout());
//create a set of constraints
GridBagConstraints c = new GridBagConstraints();
//add the top bar
c.gridx = 0; c.gridy = 0;
c.gridwidth = 7; c.gridheight = 1;
c.weightx = 1.0; c.weighty = .5;
c.fill = GridBagConstraints.BOTH;
pane.add(panels[0], c);
//add the day labels
for(int i = 0; i < 7; i++) {
c.gridx = i; c.gridy = 1;
c.gridwidth = 1; c.gridheight = 1;
c.weightx = 1.0; c.weighty = .2;
c.fill = GridBagConstraints.BOTH;
pane.add(panels[i+1], c);
//add the day boxes
int panelAt = 8;
for(int row = 0; row < 6; row++) {//each row
for(int col = 0; col < 7; col++) {//each column
c.gridx = col; c.gridy = row + 2;
c.gridwidth = 1; c.gridheight = 1;
c.weightx = 1.0; c.weighty = 1.0;
c.fill = GridBagConstraints.BOTH;
pane.add(panels[panelAt], c);
panelAt++;
public JPanel getPanel() {
return pane;
public static void main(String[] args) {
JFrame frame = new JFrame("GridBagLayoutDemo");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
TCalander cal = new TCalander(500, 500);
frame.setContentPane(cal.getPanel());
frame.setSize(500,500);
frame.setVisible(true);