Java GUI : สอบถามการใช้ JPanel ย้ายไปยัง JPanel ที่อยู่ต่าง Class กันของ eclipse ครับ

getContentPane().removeAll();

// Home Menu
		JMenuItem home = new JMenuItem("\u0E2B\u0E19\u0E49\u0E32\u0E41\u0E23\u0E01");
		home.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
				PanelMainClass Pmc = new PanelMainClass();
				Pmc.setBorder(BorderFactory.createTitledBorder(""));
            	frmMathProjectT.getContentPane().removeAll();
            	frmMathProjectT.getContentPane().add(Pmc, BorderLayout.CENTER);
            	frmMathProjectT.getContentPane().doLayout();

package com.java.image;

import javax.swing.JPanel;
import javax.swing.JButton;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;

public class GGG extends JPanel {

	/**
	 * Create the panel.
	 */
	public GGG() {
		setLayout(null);
		
		JPanel panel = new JPanel();
		panel.setBounds(0, 0, 450, 300);
		add(panel);
		panel.setLayout(null);
		
		JButton btnNewButton = new JButton("back home");
		btnNewButton.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e) {
PanelMainClass test = new PanelMainClass();
                    test.getContentPane().removeAll();
			}
		});
		btnNewButton.setBounds(174, 230, 89, 23);
		panel.add(btnNewButton);

	}

}