Getting rid of the top panel of a JFileChooser

Try this:

   fc.remove(1)

(where fc is a JFileChooser instance)
This example shows you also how to remove only part of the top panel:

import javax.swing.filechooser.*;
import javax.swing.event.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.io.*;
 
public class Main extends JFrame {
   public Main() {
      super("JFileChooser Demonstration");
 
      getContentPane().setLayout(new FlowLayout()); 
      final JFileChooser fc = new JFileChooser();
 
      // Remove the whole top panel of JFileChooser 
      fc.remove(1);
 
      // Disable the create new folder button 
      //((JPanel)fc.getComponent(1)).getAccessibleContext()
      .getAccessibleChild(9).getAccessibleContext()
      .getAccessibleComponent().setEnabled(false);
 
      // Hide the create new folder button
      //((JPanel)fc.getComponent(1)).getAccessibleContext()
      .getAccessibleChild(9).getAccessibleContext()
      .getAccessibleComponent().setVisible(false); 
 
      JButton button = new JButton("Show JFileChooser");
      button.addActionListener(new ActionListener() {
         public void actionPerformed(ActionEvent ae) {
            int r = fc.showOpenDialog(Main.this); 
  
            if (r == JFileChooser.APPROVE_OPTION)
               System.out.println("Selected: " + fc.getSelectedFile());
         }
      });
 
      getContentPane().add(button); 
  
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent e) {
            System.exit(0);
         }
      });
   }
 
   public static void main(String[] args) {
      Main main = new Main();
      main.pack();
      main.setVisible(true);
   }
}