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POAspectJ Load time weaver doesn't detect all classes
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copied!<p>I am using Spring's declarative transactions (the @Transactional annotation) in "aspectj" mode. It works in most cases exactly like it should, but for one it doesn't. We can call it <code>Lang</code> (because that's what it's actually called).</p> <p>I have been able to pinpoint the problem to the load time weaver. By turning on debug and verbose logging in aop.xml, it lists all classes being woven. The problematic class <code>Lang</code> is indeed not mentioned in the logs at all.</p> <p>Then I put a breakpoint at the top of <code>Lang</code>, causing Eclipse to suspend the thread when the <code>Lang</code> class is loaded. This breakpoint is hit while the LTW weaving other classes! So I am guessing it either tries to weave <code>Lang</code> and fails and doesn't output that, or some other class has a reference that forces it to load <code>Lang</code> before it actually gets a chance to weave it.</p> <p>I am unsure however how to continue to debug this, since I am not able to reproduce it in smaller scale. Any suggestions on how to go on?</p> <hr> <p><em>Update:</em> Other clues are also welcome. For example, how does the LTW actually work? There appears to be a lot of magic happening. Are there any options to get even more debug output from the LTW? I currently have:</p> <pre><code><weaver options="-XnoInline -Xreweavable -verbose -debug -showWeaveInfo"> </code></pre> <hr> <p>I forgot tom mention it before: <strong>spring-agent</strong> is being used to allow LTW, i.e., the <code>InstrumentationLoadTimeWeaver</code>.</p> <hr> <p>Based on the suggestions of Andy Clement I decided to inspect whether the AspectJ transformer is ever even passed the class. I put a breakpoint in <code>ClassPreProcessorAgent.transform(..)</code>, and it seems that the <code>Lang</code> class never even reaches that method, despite it being loaded by the same class loader as other classes (an instance of Jetty's WebAppClassLoader).</p> <p>I then went on to put a breakpoint in <code>InstrumentationLoadTimeWeaver$FilteringClassFileTransformer.transform(..)</code>. Not even that one is hit for <code>Lang</code>. And I believe that method should be invoked for <em>all</em> loaded classes, regardless of what class loader they are using. This is starting to look like:</p> <ol> <li>A problem with my debugging. Possibly <code>Lang</code> is not loaded at the time when Eclipse reports it is</li> <li>Java bug? Far-fetched, but I suppose it does happen.</li> </ol> <hr> <p>Next clue: I turned on <code>-verbose:class</code> and it appears as if <code>Lang</code> <em>is</em> being loaded prematurely - probably before the transformer is added to Instrumentation. Oddly, my Eclipse breakpoint does not catch this loading.</p> <p>This means that Spring is new suspect. there appears to be some processing in <code>ConfigurationClassPostProcessor</code> that loads classes to inspect them. This could be related to my problem.</p> <hr> <p>These lines in <code>ConfigurationClassBeanDefinitionReader</code> causes the <code>Lang</code> class to be read:</p> <pre><code>else if (metadata.isAnnotated(Component.class.getName()) || metadata.hasAnnotatedMethods(Bean.class.getName())) { beanDef.setAttribute(CONFIGURATION_CLASS_ATTRIBUTE, CONFIGURATION_CLASS_LITE); return true; } </code></pre> <p>In particular, <code>metadata.hasAnnotatedMethods()</code> calls <code>getDeclaredMethods()</code> on the class, which loads all parameter classes of all methods in that class. I am guessing that this might not be the end of the problem though, because I think the classes are supposed to be unloaded. Could the JVM be caching the class instance for unknowable reasons?</p>

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