Why isnt this working? add container to frame..

Question

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class MortgageCalcFrame {
    private static void createAndShowGUI() {
        //Create and set up the window.
        JFrame frame = new JFrame("Mortgage calculator");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        // Add's a container in the frame
        Container content = new Container();
        frame.getContentPane().add(content, BorderLayout.SOUTH);
        JButton btn = new JButton("test");
        content.add(btn, BorderLayout.EAST);
        JTextField input = new JTextField(5);
        frame.getContentPane().add(input, BorderLayout.CENTER);
        //Display the window.
        frame.pack();
        frame.setVisible(true);
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
}

Answer 1

Well the problem you got is that the layout of a Container is null. You've got several options here.
1. You set a layout for your container like this
    Container content = new Container();
    content.setLayout(new FlowLayout());2. You use a different container that inherits from container like Panel or JPanel since this one already got a FlowLayout set.
Panel content = new Panel();or
JPanel content = new JPanel(); //better since you're currently mixing Swing components and AWT.