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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/542552#542552">View the full discussion</a>
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<div class="jive-rendered-content"><blockquote class="jive-quote"><p>Kabir Khan wrote:</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>I have done some performance measurements where I compare the times taken creating the following class, using javassist.bytecode.* and asm</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><div> </div><pre class="jive-pre"><code class="jive-code jive-java"><span style="color: navy;"><strong>public</strong></span> <span style="color: navy;"><strong>class</strong></span> JavassistMethod1 <span style="color: navy;"><strong>implements</strong></span> JavassistMethod
<span style="color: navy;">{</span>
  <span style="color: navy;"><strong>public</strong></span> Object invoke(Object target, Object[] args) <span style="color: navy;"><strong>throws</strong></span> Throwable
  <span style="color: navy;">{</span>    
      <span style="color: navy;"><strong>return</strong></span> Integer.valueOf(((SomeClass)target).someMethod(((Integer)args[0]).intValue(), (String)args[1])).intValue();
  <span style="color: navy;">}</span>
<span style="color: navy;">}</span>
</code></pre>
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<div>Which would be used to call the method:</div>
<pre class="jive-pre"><code class="jive-code jive-java">    <span style="color: navy;"><strong>int</strong></span> someMethod(<span style="color: navy;"><strong>int</strong></span> i, String);
</code></pre>
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<div>The basic flow for what I do for both approaches is the same, whereby I do the following lots of times to generate lots of similar classes:</div>
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<div>A) - Create class structure</div>
<div>B) - Add default constructor with body to call super</div>
<div>C) - Add invoke method</div>
<div>C1) - Add invoke method body</div>
<div>D) - Convert class structure from A) into byte[]</div>
<div>E) - Define java.lang.Class by calling ClassLoader.defineClass()</div>
<div>F) - Call Class.newInstance()</div>
</blockquote><p>Chiba has done some great work on creating a new API for Javassist tailor made to create new classes. Taking the defining of the class and instantiating it out of the equation (since that is JVM stuff out of our control), so we do A-D so we have the bytes ready to create the class the times are now for creating 20000 JavassistMethod implementations</p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><table border="1" cellpadding="3" cellspacing="0" style="width: 100%; border: 1px solid #000000;"><tbody><tr><th align="center" style="background-color: #6690bc;" valign="middle"><span style="color: #ffffff;"><strong>ASM</strong></span></th><th align="center" style="background-color: #6690bc;" valign="middle"><span style="color: #ffffff;"><strong>Javassist ClassFile</strong></span></th><th align="center" style="background-color: #6690bc;" valign="middle"><span style="color: #ffffff; font-weight: 800; ">JavassistClassFileWriter</span></th></tr><tr><td>476</td><td>1030</td><td>356</td></tr><tr><td>613</td><td>1056</td><td>269</td></tr><tr><td>483</td><td>1076</td><td>309</td></tr><tr><td>464</td><td>1001</td><td>357</td></tr><tr><td>383</td><td>1186</td><td>315</td></tr></tbody></table><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p style="min-height: 8pt; height: 8pt; padding: 0px;"> </p><p>I have attached the modified benchmark</p></div>
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<p style="margin: 0;">Reply to this message by <a href="http://community.jboss.org/message/542552#542552">going to Community</a></p>
<p style="margin: 0;">Start a new discussion in JBoss Microcontainer Development at <a href="http://community.jboss.org/choose-container!input.jspa?contentType=1&containerType=14&container=2115">Community</a></p>
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