I wrote a simple program with a gui that basically took user input and made a MLA citation from it. I recently found out I can have it initialize in one click by making it a .jar file and decided it would be a good idea. However, when I try, it says that it cannot find the main method, even though I have it in one of my files. Can someone please help? Here are the files.

I've been using the commands (I'm not sure which is right, another place I need help)
jar cmf mainClass.txt MLA.jar webs.java books.java mlas.java
and
jar cmf mainClass.txt MLA.jar webs.class books.class mlas.class

webs.java and books.java are just two files that create new JFrames with more content.

The program works outside of the .jar file.

Here is mlas.java
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

public class mlas extends JFrame implements ActionListener
{
private JLabel words;
public mlas()
{
JPanel buttonPanel;
JButton quitButton;
Container contentPane;
JButton website;
JButton book;

buttonPanel=new JPanel();
quitButton=new JButton("Exit");
book = new JButton("Book");
website=new JButton("Website");
words = new JLabel("Inacuracies in citation may exist. Manually double checking is reccomended. * denotes required field");
contentPane=getContentPane();

contentPane.setBackground(Color.LIGHT_GRAY);
setSize(600, 320);
setTitle("MLA Citations");

buttonPanel.add(book);
buttonPanel.add(website);
buttonPanel.add(quitButton);

contentPane.setLayout(new BorderLayout());
contentPane.add(buttonPanel, BorderLayout.NORTH);
contentPane.add(words, BorderLayout.LINE_END);

website.addActionListener(this);
quitButton.addActionListener(this);
book.addActionListener(this);

setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setVisible(true);
}

public void actionPerformed(ActionEvent e)
{

if (e.getActionCommand().equals("Book"))
{
Books z= new Books();
}

else if (e.getActionCommand().equals("Online Source"))
{
Webs y= new Webs();
}

else if (e.getActionCommand().equals("Exit"))
{
System.exit(0);
}
}
public static void main(String[] args)
{
mlas x = new mlas();
}
}

and heres mainClass.txt
Main-Class: mlas

Thank you!