Strange Behaviour of JTabbedPane.Please Guide

Question

Folks
I am getting a strange Error regarding JTabbedPane.
In my main class,I am using :
addTab
("One",
null,
new A(),
"Test One");
nothing happens.The contents of class A is not displayed.
But when I say:
addTab
("One",
null,
new A().call(),
"Test One");
the contents of Class A() is displayed..
Why cant i use new A() DIRECTLY....
Any idea on this?
Class A(){
// This does not work
A(){
new B();
// This works..
public void call(){
return new B();
Even in the constructor of A when I say 'return new B()'..this doesnt work
Any one experienced this..

Answer 1

Instantiating (making a new) B in the constructor of A is okay. But the new B must be added to the content pane of A for it to be displayed in A.
import java.awt.*;
import javax.swing.*;
public class bhuru extends JFrame {
  public bhuru() {
    JTabbedPane tabbedPane = new JTabbedPane();
    tabbedPane.addTab("One", null, new A(), "new A()");
    tabbedPane.addTab("Two", null, new A().getB(), "new A().getB()");
    tabbedPane.addTab("Three", null, new B(), "new B()");
    tabbedPane.addTab("Four", null, new C(), "new C()");
    getContentPane().add(tabbedPane);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(400,300);
    setLocationRelativeTo(null);
    setVisible(true);
  public static void main(String[] args) {
    new bhuru();
class A extends JPanel {
  public A() {
    new B();
  // void return type won't work here
  // you are returning an object of type B
  public B getB() {
    return new B();
class B extends JPanel {
  public B() {
    setPreferredSize(new Dimension(250,175));
    setBackground(Color.red);
class C extends JPanel {
  public C() {
    add(new B());
    setBackground(Color.blue);
}