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<a href="http://community.jboss.org/index.jspa" style="text-decoration: none; color: #E1E1E1">Community</a></h1>
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JBoss Reflect Performance Javassist vs Introspection
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reply from <a href="http://community.jboss.org/people/kabir.khan%40jboss.com">Kabir Khan</a> in <i>JBoss Microcontainer Development</i> - <a href="http://community.jboss.org/message/538013#538013">View the full discussion</a>
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<div class="jive-rendered-content"><p>To summarize, the steps I want to take here are:</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>1) Decide if we should bother to do parameter checking. If we decide to keep it, it should be done by Javassist[Method/Constructor/Field]Info and not in the generated JavassistMethod/-Constructor/-Field implementations. This can easily be turned off in the generated classes by passing in check=false to the JavassistMemberFactory create methods.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>2) Enable stats for the JavassistMethodInfo.invoke(), JavassistConstructorInfo.newInstance() and JavassistFieldInfo.get()/set() so we can run AS with that and get an idea of the usage of these joinpoints.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>3) Avoid creating too many JavassistMethod/-Constructor/-Field implementations. There is an overhead associated with creating these, both in terms of filling up PermGenSpace and in CPU time since each member that gets one of these needs to first generate the class and then to call ClassLoader.defineClass() which takes time. JavassistMethod/-Constructor/-Field should only be generated for Javassist[Method/Constructor/Field]Infos whose invoke()/newInstance()/get()/set() are called a lot. The data from 2) should give us some understanding of which members they are. Javassist[Method/Constructor/Field]Infos which are NOT called a lot should simply use reflection to call the target member. I think reflection should be the default.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>4) Come up with some differentiator (as mentioned earlier) to be able to specify if a member should have JavassistMethod/-Constructor/-Field generated or not.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>5) Let's stay with Javassist for now, and go with asm if javassist can not be improved upon in the time allowed. Creating yesterday's benchmark, I found as long as you have got the hang of one it is quite easy to look at the other.</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>I will start off by doing some work on 2) and let you know how far I get with the others before Tuesday</p></div>
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