If a user adds a component that already exists in JTabbedPane will throw a ArrayIndexOutOfBoundsException. The problems seems that we get an invalid index
after deletion. We need to insert current index of tabbedpane not the pages.size(). 

TestCode:

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

public class AddSameComp extends JFrame implements ActionListener{
  String path;
  Container contentPane = getContentPane();
  JTabbedPane jtp = new JTabbedPane();
  JButton b1 = new JButton("button in panel 1");
  JButton b2 = new JButton("button in panel 2");
  JPanel panelOne = new JPanel();
  JPanel panelTwo = new JPanel();  
  JPanel panelThree = new JPanel();
  JLabel newTab = new JLabel("This is a New Tab Added");
  String textOut;
  

  private JPanel buttonPanel = new JPanel();
  private JPanel bottomPanel = new JPanel(new BorderLayout());
  private JPanel statusPanel = new JPanel();
  Object o;
  
  private JLabel label = new JLabel("Press Blue \"Add Component one again\" button to start test.");
  private JButton start;
  private JButton pass;
  private JButton fail;

  AddSameComp() {
    super("AddSameComp Test");
    
    // Add Invoke Buttons
    
    start = addButton(buttonPanel,"Add Component one again",Color.blue);
    pass = addButton(buttonPanel,"Pass",Color.green);
    fail = addButton(buttonPanel,"Fail",Color.red);
    bottomPanel.add(buttonPanel,BorderLayout.NORTH);
    statusPanel.add(label);
    bottomPanel.add(statusPanel,BorderLayout.SOUTH);

    contentPane.add(bottomPanel,BorderLayout.SOUTH);

    
    // Add Tab Panes Here!!!
    jtp.add("Panel One",panelOne);
    jtp.add("Panel Two",panelTwo);

    contentPane.add(jtp,BorderLayout.CENTER);
 
    // Add Window handler
    addWindowListener(new WindowAdapter(){ 
      public void windowClosing(WindowEvent event){ System.exit(0);}
    });
  }

   public void actionPerformed(ActionEvent evt) {
    String cmd = evt.getActionCommand();
    if (evt.getSource() == pass) {
      System.out.println("Test Passed");
      System.exit(0);
    }
    else if (evt.getSource() == fail) {
      System.out.println("Test Failed");
      System.exit(1);
    }
    else if (evt.getSource() == start) {
      try {
	jtp.add("Panel One",panelOne);
	label.setText("T est passed! ArrayIndexOutOfBoundsException was not thrown!!");
      }
      catch (ArrayIndexOutOfBoundsException e) {
	label.setText("Test Failed! ArrayIndexOutOfBoundsException was thrown!!");
      }
    }
  }

  public JButton addButton(JPanel addComponent, String name, Color color) {
    JButton b = new JButton(name);
    b.setBackground(color);
    b.addActionListener(this);
    addComponent.add(b);
    return b;
  }

  public static void main(String[] args) {
    
    AddSameComp t = new AddSameComp();
    t.setSize(450,300);
    t.setVisible(true);
  }    
}