JDialog里的控件不能统制大小啊?

JDialog里的控件不能控制大小啊?????????????
Jdialog的例子,为什么那个dialog里的控件不能控制大小啊?????????????


import   java.awt.*;

import   javax.swing.JButton;
import   javax.swing.JDialog;


public   class   Dialoginput   extends   JDialog{
JButton   jb,jc;
/**
  *  
  */
private   static   final   long   serialVersionUID   =   1L;
Dialog   parent;
Dialoginput(Frame   f,String   s,boolean   modal)
{
super(f,s,modal);
parent=(Dialog)f;
jb=new   JButton( "d ");
jb.setBounds(44,   44,   44,   33);
jc=new   JButton( "ddd ");
jc.setBounds(44,   44,   44,   33);
add(jb);
add(jc);
this.setSize(100,100);
}


}
/////////////
import   java.awt.Container;
import   java.awt.event.ActionEvent;
import   java.awt.event.ActionListener;

import   javax.swing.JButton;
import   javax.swing.JFrame;


public   class   Dialog   extends   JFrame{
JButton   jb;
Dialoginput   diain;
Dialog()
{       Container   content=getContentPane();
        setSize(400,400);
        setVisible(true);
        setLayout(null);
jb=new   JButton( "d ");
jb.setBounds(55,   55,   55,   55);
content.add(jb);
jb.addActionListener(new   ActionListener(){
public   void   actionPerformed(ActionEvent   e)
{
x(e);
}
});

}
public   static   void   main(String   []   agrs)
{
new   Dialog();
}
public   void   x(ActionEvent   e)
{
this.diain=new   Dialoginput(this, "d ",true);
this.diain.show();
}
}


------解决方案--------------------
主要是需要一个布局管理器

1 ---------------------------
//Dialoginput(Frame f,String s,boolean modal)

Dialoginput(JFrame f,String s,boolean modal)
{
super(f,s,modal);
parent=(Dialog)f;
jb=new JButton( "d ");
jb.setBounds(44, 44, 44, 33);
jc=new JButton( "ddd ");
jc.setBounds(44, 44, 44, 33);
//布局管理
this.setLayout(new FlowLayout());
add(jb);
add(jc);
this.setSize(100,100);
}

2--------------------------

import javax.swing.JFrame;
Dialog()
{ Container content=getContentPane();
setSize(400,400);
//setVisible(true);
setLayout(null);
jb=new JButton( "d ");
jb.setBounds(55, 55, 55, 55);
content.add(jb);
jb.addActionListener(new ActionListener(){
public void actionPerformed(ActionEvent e)
{
x(e);
}
});
setVisible(true);//最后设置可以化.
}