Finally figured out the problem, have added the layout again as like it is added in the generated code and it worked
jButton3.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
System.out.println("In the action");
JLabel imgLabel = new JLabel(new ImageIcon(this.getClass().getResource( "/resource/images/cd-dvd-icon.png")));
jPanel2.add(imgLabel);
jPanel2.revalidate();
jPanel2.repaint();
jPanel2.setLayout(jPanel2Layout);
jPanel2Layout.setHorizontalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGap(24, 24, 24)
.addComponent(jButton3)
.addGap(59, 59, 59)
.addComponent(jToggleButton1)
.addGap(50, 50, 50)
.addComponent(imgLabel)
.addContainerGap(235, Short.MAX_VALUE))
);
jPanel2Layout.setVerticalGroup(
jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
.addGroup(jPanel2Layout.createSequentialGroup()
.addGap(33, 33, 33)
.addGroup(jPanel2Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
.addComponent(jToggleButton1)
.addComponent(jButton3))
.addGap(59, 59, 59)
.addComponent(imgLabel)
.addContainerGap(368, Short.MAX_VALUE))
);
}
});