Can i track an IMAP mail reply?

I am working on an IMAP client using java mail. We currently have a requirement of creating a "group by conversation" feature where user can view mails as conversation (Refer to how gmail groups mails that are replied and forwarded)

I am able to retrieve mails from the server, but in the mail parts i recieve, the replied mail is "fused" with actual mail and is treated like actual mail content.

eg: initial mail:

<div>This is the initial mail.</div>

replied mail:

This is the response Mail<br><br>
<div class="gmail_quote">
On Wed, Aug 26, 2009 at 4:26 PM, [censored] 
<span dir="ltr">&lt;
<a href="mailto:[censored]@[censored].com">
[censored]@[censored].com
</a>
&gt;
</span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
    <div>This is the initial mail.</div>
    <div></div>
</blockquote>
</div>
<br>

as shown above, there is no indication of what was actual and what was replied mail, how then is it possible to provide a grouping like gmail (regardless of server from where mail is read from)?

Solution

If you get the raw source of the messages you can relate messages to one another by looking at the following headers:

Message-ID: <097819EBC7F79F4A850C8F088D35927302442A82AA@xxxxxxxxxxxxxxxxxxx>
References: <4A8BE8F3.2060007@xxxxxxxxxxxxxx>
In-Reply-To: <4A8BE8F3.2060007@xxxxxxxxxxxxxxx>