Help with JTextBox please?

[MW130]

Hi guys, before I tell you my problem I just want you to know that I looked online but nowhere did I find why this error is happening; I am creating a panel and adding it to the JFrame and then adding a textbox to the panel. The program runs, but the textbox is not displayed? Did I do it completely wrong or is it a quick fix? Thank you!

import javax.swing.*;
import javax.swing.JTextField;
import java.awt.*;
public class Box {
Box(){
     JFrame f =  new JFrame("Text Box");
     f.setSize(400,400);
     f.setVisible(true);
     f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
     JPanel p = new JPanel();
      f.add(p);
      JTextField t = new JTextField("Enter numbers here.", 15);
      p.add(t);
  }
public static void main(String[] args) {
new Box();
    }
}

[Fubarable]

Resize the JFrame and tell me what happens.... the JTextField appears doesn't it?

Solution:
1) don't set the size of the JFrame.
2) Instead set the preferredSize of the JPanel (or override its getPreferredSize() method)
3) First add your components to the JFrame
4) *Then* call pack and setVisible(true) on the JFrame *after* adding all components to it.

[MW130]

Resize the JFrame and tell me what happens.... the JTextField appears doesn't it?

Solution:
1) don't set the size of the JFrame.
2) Instead set the preferredSize of the JPanel (or override its getPreferredSize() method)
3) First add your components to the JFrame
4) *Then* call pack and setVisible(true) on the JFrame *after* adding all components to it.

Oh... It did work after resizing it! Ok, I got it; from now on rather than set the size of the JFrame I will set a preferred size for the panel. Thank you so much Fubarable.