JTableHeader not showing

[marc weber]

This is my first experience using a JTable, and I'm using a DefaultTableModel. What do I need to do to get the header to show?

In the test code below, I've gotten to the point of setting the header value (I think), but I'm stuck after that. I'm sure this is something simple, but I'm missing it.

import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
 
class TableTest extends JFrame {
  TableTest() {
    setTitle("TableTest");
    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 
    JPanel contentPanel = new JPanel();
    String[] rowData = { "abc", "def" };
 
    DefaultTableModel model = new DefaultTableModel();
    model.addColumn("Col A");
    model.addColumn("Col B");
    model.addRow(rowData);
 
    [B]JTable mainTable = new JTable(model);
    JTableHeader header = mainTable.getTableHeader();
    TableColumnModel colModel = header.getColumnModel();
    TableColumn column = colModel.getColumn(0);
    column.setHeaderValue("Column A Header");
    //???[/B]
 
    contentPanel.add(mainTable);
    JScrollPane contentScroll = new JScrollPane(contentPanel);
 
    JPanel topPanel = new JPanel(new BorderLayout());
    topPanel.add(contentScroll);
 
    add(topPanel, BorderLayout.CENTER);
    pack();
    setVisible(true);
  }
 
  public static void main(String[] args) {
    TableTest t = new TableTest();
  }
}

[Paul Clapham]

If I'm not mistaken, you only get the column headings if your JTable is in a JScrollPane. Yours isn't, it's in a JPanel that's in the JScrollPane. The intermediate panel looks unnecessary to me.

[marc weber]

Sure enough, that seems to be it! Thanks for the help.

I broke this out of a much larger piece of code to isolate the problem, and there are a still some unnecessary pieces here. I see I was headed down the wrong path with the code I had in bold.