Why am I getting this error? How do I add confirm message to button press?

Question

Using Java Studio Creator.
I do not understand why I am getting the following page error:
Description: An unhandled exception occurred during the execution of the web application. Please review the following stack trace for more information regarding the error.
Exception Details: java.lang.IndexOutOfBoundsException
Index: 0, Size: 0
Possible Source of Error:
Class Name: java.util.ArrayList
File Name: ArrayList.java
Method Name: RangeCheck
Line Number: 546
======================================================================
I have a page that works.
It has a button that is created in the session bean code with the following java:
button = (HtmlCommandButton)application.createComponent(HtmlCommandButton.COMPONENT_TYPE);
button.setActionListener( application.createMethodBinding("#{ScheduleEditSessionBean.mainApply}", new Class[]{ActionEvent.class} ));
button.setId( "applyUndates" );
button.setType( "submit" );
button.setTitle( "Apply updates.");
button.setValue( "Apply" );
button.setStyle(style);
children.add(button);
When the button is pushed, it calls the following session bean method:
public void mainApply(ActionEvent actionEvent)
updateScheduleData();
scheduleAdjustFlag = 1;
dataApplied = true;
dataSaved = false;
addControls();
This all works just fine - no errors
====================================================================
I wanted to add confirmation to the button press, so I removed the action listener for this button and added
a javascript function call for the onclick method
button = (HtmlCommandButton)application.createComponent(HtmlCommandButton.COMPONENT_TYPE);
style = "text-align: center; font-family: 'Arial','Helvetica',sans-serif; " + font + " height: 22px; width: 115px";
// Commented out this line button.setActionListener( application.createMethodBinding("#{ScheduleEditSessionBean.mainApply}", new Class[]{ActionEvent.class} ));
button.setOnclick("confirmApply()"); // Added this line.
button.setId( "applyUndates" );
button.setType( "submit" );
button.setTitle( "Apply updates.");
button.setValue( "Apply" );
button.setStyle(style);
children.add(button);
I added a dummy button to the page that has the following call to execute the mainApply method in the sessioon bean.
The button action just calls the mainApply() method in the session bean
public String mainApplyBtn_action() {
seb.mainApply();
return null;
Added the javascript to the page that simply pushes the dummy button if confirmed.
function confirmApply()
if( confirm( 'Are you sure you want to Apply these changes?' ) )
form1["form1:mainApplyBtn"].click();
The session bean method looks like this it is the same method as before, but without the action event argument.
public void mainApply()
lsb.logMsg( "<ScheduleEditBean.mainApply> Main apply pushed" );
updateScheduleData();
scheduleAdjustFlag = 1;
dataApplied = true;
dataSaved = false;
addControls();
==================================================================================
Now, when I push the original 'Apply' button, I get the confirmation box just like I expected.
But when I confirm the question, I get the error at the top of this post.
If I push the 'dummy button' directly, I do not get the error.
I do not understand why I should be gettng this error.
Can anyone give me a clue as to why this change would cause the problem?
The error is related to an ArrayList.
I use several of these on the page, but they should be filled with data in the preRender method of the page.
Can anyone suggest a way that I can add confirmation to a button that is created under program control?
Thanks

Answer 1

Make use of the fact that when an onclick event of a button returns 'false', the action will not be taken.
Pseudocode:<h:commandButton value="submit" action="#{myBean.action}" onclick="return confirm('Are you sure?');" />