When adding a customized JPanel, everything disappears

I am trying to write an application that uses a JSplitPane. I am
working on customizing the JPanel on the left side of the SplitPane.
So far, the only component I've added to the JPanel is a JScrollPane.
When I add the scrollpane, my splitPane nor my Menu appear when I run
the program. I've pasted my code below. If someone could explain to
me how to fix it, and more importantly, why it occurs, I would greatly
appreciate it. Thanks

CODE*********************************
****************************************

import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JSplitPane;
import java.awt.Container;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.sql.SQLException;

public class Main extends JFrame implements ActionListener{

    private String database = "adsadf";
    private DataConnection dc;
    private LeftPanel leftPanel;
    private JPanel rightPanel;

    public Main() {

        setVisible(true);
        setSize(500,500);
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setExtendedState(JFrame.MAXIMIZED_BOTH);

        leftPanel = new LeftPanel();
        rightPanel = new JPanel();

        JSplitPane splitPane = new
JSplitPane(JSplitPane.HORIZONTAL_SPLIT, leftPanel, rightPanel);
        splitPane.setSize(getSize());
        splitPane.setDividerLocation(150);

        Container c = getContentPane();
        c.add(splitPane);

        createMenuBar();
    }

    private void createMenuBar(){
        JMenuBar menuBar = new JMenuBar();
        JMenu menu = new JMenu("File");
        menuBar.add(menu);

        JMenuItem item = new JMenuItem("Exit");
        item.setActionCommand("exit");
        item.addActionListener(this);
        menu.add(item);

        setJMenuBar(menuBar);
    }

    public void actionPerformed(ActionEvent ae){
        if(ae.getActionCommand().equals("exit")){
            System.exit(0);
        }
    }

    public static void main(String[] args) {
        Main main = new Main();
    }

}

//***************************************************
//******CUSTOM JPANEL***********************
//***************************************************

import javax.swing.JPanel;
import javax.swing.JScrollPane;

public class LeftPanel extends JPanel{

    JScrollPane scroller;

    public LeftPanel() {
        super();

        scroller = new JScrollPane();
        add(scroller);

    }

}