JTable header not showing

Same problem I have face You have to add the JTable to the JScrollPane then add JscrollPane to JFrame e.g.

JTable table = new JTable();
JScrollPane scrollPane= new  JScrollPane(table);
frame.add(scrollPane);

Start by removing

panel.add(table.getTableHeader());

The JTable is designed to add it's header to the JScrollPane. An instance of a component can only belong to a one parent/container, the above line is removing it from the scrollpane

Also, change this...

panel.add(table);

To

panel.add(scrollPane);

Best JTable Example (Working smoothly just paste in editor and execute as Java application) with dynamic data :

import java.awt.EventQueue;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.table.DefaultTableModel;

public class TableTest {

private JFrame frame;
private JTable table;

/**
 * Launch the application.
 */
public static void main(String[] args) {
    EventQueue.invokeLater(new Runnable() {
        public void run() {
            try {
                TableTest window = new TableTest();
                window.frame.setVisible(true);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

/**
 * Create the application.
 */
public TableTest() {
    initialize();
}

/**
 * Initialize the contents of the frame.
 */
private void initialize() {
    frame = new JFrame();
    frame.setBounds(100, 100, 450, 300);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().setLayout(null);

    table = new JTable();

    DefaultTableModel daDefaultTableModel = new DefaultTableModel(0, 0);

    String[] columnNames = new String[] {"Column Header1", "Column Header2", "Column Header3"};

    daDefaultTableModel.setColumnIdentifiers(columnNames);

    //Dummy data for Table
    daDefaultTableModel.addRow(new Object[] {"Test1","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test2","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test3","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test4","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test5","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test6","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test7","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test8","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test9","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test10","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test11","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test12","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test13","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test14","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test15","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test16","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test17","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test18","Test2","Test3"});
    daDefaultTableModel.addRow(new Object[] {"Test19","Test2","Test3"});

    table.setModel(daDefaultTableModel);

    JScrollPane scrollPane = new JScrollPane(table);
    scrollPane.setBounds(10, 38, 414, 212);
    frame.getContentPane().add(scrollPane);



  }
}