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href="http://www-105.ibm.com/developerworks/education.nsf/dw/java-onlinecourse-bytitle">Education - online courses</a></font><br x="7"><img src="imagemaster/masthead.jpg" alt="Building a Java chat server"></td><td width="*" valign="bottom" align="right"><a border="0" href="j-chat.zip"><img alt="Download tutorial zip file" border="0" src="../i/icon-zip.gif"></a><a border="0" href="j-chat-ltr.pdf"><img alt="View letter-sized PDF file" border="0" src="../i/icon-pdf-ltr.gif"></a><a border="0" href="j-chat-a4.pdf"><img alt="View A4-sized PDF file" border="0" src="../i/icon-pdf-a4.gif"></a><a href="javascript:void newWindow()" border="0"><img alt="E-mail this tutorial to a friend" border="0" src="../i/icon-email.gif"></a></td></tr><tr><td height="2" colspan="2"><img height="2" width="1" src="http://www.ibm.com/i/c.gif"></td></tr></table><TABLE border="0" cellpadding="0" cellspacing="0" width="100%"><TR><TD width="150" height="1" bgcolor="#000000" colspan="6"><IMG alt="" height="1" 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border="0" height="25" width="562" src="imagemaster/titlebar2.jpg" alt="2. Introduction"></td></tr><tr><td bgcolor="ffffff" width="15"> </td><td bgcolor="ffffff" width="12"> </td><td valign="top" align="left" bgcolor="ffffff" width="*"><p><br x="7"><table cellspacing="0" cellpadding="0" border="0"><tr><td width="90%"><font size="4" face="Verdana, Arial, Helvetica"><b>Why a framework?</b></font></td><td width="200" align="right"><font size="1" face="Verdana, Arial, Helvetica"><nobr> page 4 of 5</nobr></font></td></tr></table><br x="7"><br x="7"></p><font size="2" face="Verdana, Arial, Helvetica"><p>The word <i>framework</i> has a technical definition within the
object-oriented community -- it means a design structure that can be
reused.</p><p>This is not the same as traditional code reuse, in which bits of code
written for one purpose (or for no particular purpose at all) are
reused for a new purpose. Rather, a framework is a reusable,
overarching structure inside which you can implement your particular
application.</p><p>One way to think of the difference between a framework and
traditional code reuse is that traditional reuse involves inserting
pre-existing elements into your particular structure, while a
framework involves inserting your particular elements into a
pre-existing framework.</p><p>The code that we'll develop in this tutorial isn't technically a
framework, in that it is not structured to allow you to
easily repurpose it for something else. Structuring it that way would
distract from the purpose of this tutorial, which is to explore basic
techniques of server programming.</p><p>However, in a design sense, it is a framework because the structure of
the code is something you'll be able to use again and again.</p><br x="7"></font></td></tr></table><TABLE border="0" cellpadding="0" cellspacing="0" width="100%"><TR><TD background="../i/sw-gold.gif"><a border="0" href="index.html" onMouseOver="iOver('topmain'); iOver('bottommain'); self.status=mainblurb; return true;" onMouseOut="iOut('topmain'); iOut('bottommain'); self.status=''; return true;"><img alt="Main menu" border="0" src="../i/main.gif" name="bottommain"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topsection'); iOver('bottomsection'); self.status=sectionblurb; return true;" onMouseOut="iOut('topsection'); iOut('bottomsection'); self.status=''; return true;" href="index2.html"><img alt="Section menu" border="0" src="../i/section.gif" name="bottomsection"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topfeedback'); iOver('bottomfeedback'); self.status=feedbackblurb; return true;" onMouseOut="iOut('topfeedback'); iOut('bottomfeedback'); self.status=''; return true;" href="j-chat-11-3.html"><img alt="Give feedback on this tutorial" border="0" src="../i/feedback.gif" name="bottomfeedback"></a></TD><TD width="100%" background="../i/sw-gold.gif"><img src="http://www.ibm.com/i/c.gif"></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topprevious'); iOver('bottomprevious'); self.status=previousblurb; return true;" onMouseOut="iOut('topprevious'); iOut('bottomprevious'); self.status=''; return true;" href="j-chat-2-3.html"><img alt="Previous" border="0" src="../i/previous.gif" name="bottomprevious"></a></TD><TD background="../i/sw-gold.gif"><a border="0" onMouseOver="iOver('topnext'); iOver('bottomnext'); self.status=nextblurb; return true;" onMouseOut="iOut('topnext'); iOut('bottomnext'); self.status=''; return true;" href="j-chat-2-5.html"><img alt="Next" border="0" src="../i/next.gif" name="bottomnext"></a></TD></TR><TR><TD width="150" height="1" bgcolor="#000000" colspan="6"><IMG alt="" height="1" width="150" src="http://www.ibm.com/i/c.gif"></TD></TR></TABLE><TABLE cellpadding="0" cellspacing="0" border="0"><TR><TD width="182"><TABLE cellpadding="0" cellspacing="0" border="0" width="182"><TR bgcolor="#000000"><TD align="center" width="60" class="mast"><a style="text-decoration: none; color: #ffffff;" class="nav" href="http://www.ibm.com/privacy/"><font face="Arial, Verdana" size="2">Privacy</font></a></TD><TD width="1" bgcolor="#959595"><img alt="" border="0" height="20" width="1" src="http://www.ibm.com/i/c.gif"></TD><TD align="center" width="60" class="mast"><a style="text-decoration: none; color: #ffffff;" class="nav" href="http://www.ibm.com/legal/"><font face="Arial, Verdana" size="2">Legal</font></a></TD><TD width="1" bgcolor="#959595"><img alt="" border="0" height="20" width="1" src="http://www.ibm.com/i/c.gif"></TD><TD align="center" width="60" class="mast"><a style="text-decoration: none; color: #ffffff;" class="nav" href="http://www.ibm.com/contact/"><font face="Arial, Verdana" size="2">Contact</font></a></TD><TD width="1" bgcolor="#959595"><img alt="" border="0" height="21" width="1" src="http://www.ibm.com/i/c.gif"></TD></TR><TR bgcolor="#ffffff"><TD><img alt="" border="0" height="1" width="1" src="http://www.ibm.com/i/c.gif"></TD></TR></TABLE></TD><TD width="100%"><TABLE cellpadding="0" cellspacing="0" border="0" width="100%"><TR height="21" bgcolor="#000000"><TD><img alt="" border="0" height="21" width="1" src="http://www.ibm.com/i/c.gif"></TD></TR><TR bgcolor="#ffffff"><TD><img alt="" border="0" height="1" width="1" src="http://www.ibm.com/i/c.gif"></TD></TR></TABLE></TD></TR></TABLE></body></html>
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