form.getContentPane().add(table);

Vector columnNames = new Vector();
     Vector data = new Vector();
        Class.forName("com.mysql.jdbc.Driver").newInstance();
        Connection con =DriverManager.getConnection("jdbc:mysql://localhost:3306/school", "colorway", "colorway");
        String sql = "Select name,lname from student";
        Statement statement = con.createStatement();
        ResultSet resultSet = statement.executeQuery(sql);
        ResultSetMetaData metaData = resultSet.getMetaData();
        int columns = metaData.getColumnCount();
    for (int i = 1; i <= columns; i++) {
        columnNames.addElement(metaData.getColumnName(i));
    }

    while (resultSet.next()) {
        Vector row = new Vector(columns);
        for (int i = 1; i <= columns; i++) {
            row.addElement(resultSet.getObject(i));
        }
        data.addElement(row);
    }
    resultSet.close();
    statement.close();
    Students form=new Students();
    JTable  table=new JTable(data, columnNames);
    form.setContentPane(table);
    form.setVisible(true);

public class Students extends javax.swing.JFrame {
//somecode
    // Variables declaration - do not modify
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;
    // End of variables declaration

    public JPanel getjpanel(){
        return this.jPanel1;
    }

    public JScrollPane getJscrollPane()
    {
        return this.jScrollPane1;
    }

    public JTable getJTable()
    {
        return this.jTable1;
    }
}

form.getContentPane().add(table);

form.getContentPane().add(button, BorderLayout.SOUTH);

import javax.swing.*;
import java.awt.event.*;
import java.awt.*;

public class MyFrame extends JFrame {
    public MyFrame () {

        String[] columns = {"one", "two", "three"};
        String[][] data = {
            {"a1", "a2", "a3"},
            {"b1", "b2", "b3"},
        };

        JTable table = new JTable(data, columns);

        getContentPane().add(new JScrollPane(table));
        getContentPane().add(new JButton("Hello"), BorderLayout.SOUTH);

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

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
                @Override
                    public void run() { new MyFrame(); }
            });
    }
}