java.lang.IncompatibleClassChangeError upon invoking getClasses() on ClassFinder instance

[chipsenkbeil]

Hi there! Was checking out the library, which looks really nice. I added the dependency through Maven Central (using sbt 0.13.7) via libraryDependencies += "org.clapper" %% "classutil" % "1.0.5", so not sure if that would be an issue since the instructions reference bin-tray. I'm compiling with Scala 2.10.4, by the way.

Anyway, I seem to have encountered an exception when invoking mainClassFinder.getClasses() where mainClassFinder is a ClassFinder instance that is using the current classpath. I'm not sure if this is a problem from me adding the dependency from Maven central - FYI, I tried bin-tray afterwards with same result - or if it's an issue with my classpath or something else. Any guidance?

Code

import java.io.File
import org.clapper.classutil.{ClassInfo, ClassFinder}

class ModuleManager(extraClassPaths: Seq[String] = Nil) {
  private lazy val mainClassFinder: ClassFinder = ClassFinder()
  private lazy val extraClassFinder: Option[ClassFinder] = Option(
    if (extraClassPaths.nonEmpty) ClassFinder(extraClassPaths.map(new File(_)))
    else null
  )

  private lazy val allClasses = mainClassFinder.getClasses() ++
    extraClassFinder.map(_.getClasses()).getOrElse(Stream.empty[ClassInfo])
  private lazy val allClassMap =
    ClassFinder.classInfoMap(allClasses.toIterator)

  lazy val modules = ClassFinder.concreteSubclasses(
    classOf[ModuleLike].getName,
    allClassMap
  )

  modules.foreach(println)
}

Exception

Exception in thread "main" java.lang.IncompatibleClassChangeError: class org.clapper.classutil.asm.EmptyVisitor has interface org.objectweb.asm.ClassVisitor as super class
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:800)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:449)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:71)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:361)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:355)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:354)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:425)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:308)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:358)
    at org.clapper.classutil.asm.ClassFile$.load(ClassFinderImpl.scala:190)
    at org.clapper.classutil.ClassFinder.org$clapper$classutil$ClassFinder$$classData(ClassFinder.scala:406)
    at org.clapper.classutil.ClassFinder$$anonfun$2.apply(ClassFinder.scala:364)
    at org.clapper.classutil.ClassFinder$$anonfun$2.apply(ClassFinder.scala:364)
    at scala.collection.immutable.Stream.map(Stream.scala:376)
    at org.clapper.classutil.ClassFinder.processOpenZip(ClassFinder.scala:364)
    at org.clapper.classutil.ClassFinder.processJar(ClassFinder.scala:318)
    at org.clapper.classutil.ClassFinder.findClassesIn(ClassFinder.scala:307)
    at org.clapper.classutil.ClassFinder.find(ClassFinder.scala:299)
    at org.clapper.classutil.ClassFinder.getClasses(ClassFinder.scala:289)
    at com.ibm.spark.kernel.module.ModuleManager.allClasses$lzycompute(ModuleManager.scala:37)
    at com.ibm.spark.kernel.module.ModuleManager.allClasses(ModuleManager.scala:37)
    at com.ibm.spark.kernel.module.ModuleManager.allClassMap$lzycompute(ModuleManager.scala:40)
    at com.ibm.spark.kernel.module.ModuleManager.allClassMap(ModuleManager.scala:39)
    at com.ibm.spark.kernel.module.ModuleManager.modules$lzycompute(ModuleManager.scala:45)
    at com.ibm.spark.kernel.module.ModuleManager.modules(ModuleManager.scala:42)
    at com.ibm.spark.kernel.module.ModuleManager.<init>(ModuleManager.scala:48)

[chipsenkbeil]

FYI, using version 1.0.3 pulled from Maven central works for me, so I'm not sure what has changed since then.

[chipsenkbeil]

FYI, using 1.0.6, this still happens when I try to invoke the method while running in ScalaTest. Running it as part of a normal program seems to work fine.

Reverting to 1.0.3 still resolves this issue for me.

[chipsenkbeil]

@bmc, this seems related to the addition of the EmptyVisitor class and the move to ASM4. I had forgotten about this issue with a fresh project until I was trying to run integration tests using classutil and hit this issue. Any idea what is happening here? Class incompatibilities are normally from binary incompatibilities when you haven't recompiled after something changed, but I've been hitting this in ScalaTest with a clean build.

Calling ClassFinder().getClasses inside ScalaTest is dying for me.

[bmc]

I've run across this one myself. I'm trying to reproduce it reliably so I can figure out what it is.

[bmc]

I've just released version 1.0.9, which includes an ASM version bump to 5.1. Can you still reproduce the problem with 1.0.9?

I'm not closing this bug yet...

[rakeshh]

I am also facing this issue. It runs fine on local machine, but when i run it on cluster(as part of some other job) it is throwing this exception.

[rakeshh]

I am getting this error with versions 1.0.9 and 1.0.10 .

[anuragranjan108]

I'm getting this issue with 1.0.10 still.

[anuragranjan108]

@bmc This is still breaking on 1.0.11

[bmc]

I confess that I'm having trouble reproducing this error. If you're still having this problem, please post additional details, such as:

• JVM version you're using, i.e., the output of java -version, not just something like "Java 8"
• Your CLASSPATH
• Your operating system and version
• Anything else you think might help

Thanks.

[whitebearded]

Hi there! I can confirm that issue using <artifactId>classutil_2.11</artifactId><version>1.0.11</version>.

• JVM: Scala version 2.11.7 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_45)
• The full classpath is a way way to long (IntelliJ). But it's containing this relevant paths:
  • /Users/USER/.m2/repository/org/clapper/classutil_2.11/1.0.11/classutil_2.11-1.0.11.jar
  • /Users/USER/.m2/repository/org/ow2/asm/asm/5.1/asm-5.1.jar
  • /Users/USER/.m2/repository/org/ow2/asm/asm-commons/5.1/asm-commons-5.1.jar
  • /Users/USER/.m2/repository/org/ow2/asm/asm-tree/5.1/asm-tree-5.1.jar
  • /Users/USER/.m2/repository/org/ow2/asm/asm-util/5.1/asm-util-5.1.jar
  • /Users/USER/.m2/repository/org/clapper/grizzled-scala_2.11/2.4.0/grizzled-scala_2.11-2.4.0.jar
• System: OS X El Capitan, 10.11.3

Error when execing val classes = finder.getClasses:
java.lang.IncompatibleClassChangeError: class org.clapper.classutil.asm.ASMEmptyVisitor has interface org.objectweb.asm.ClassVisitor as super class at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:760) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:467) at java.net.URLClassLoader.access$100(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:368) at java.net.URLClassLoader$1.run(URLClassLoader.java:362) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:361) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at java.lang.ClassLoader.defineClass1(Native Method) at java.lang.ClassLoader.defineClass(ClassLoader.java:760) at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142) at java.net.URLClassLoader.defineClass(URLClassLoader.java:467) at java.net.URLClassLoader.access$100(URLClassLoader.java:73) at java.net.URLClassLoader$1.run(URLClassLoader.java:368) at java.net.URLClassLoader$1.run(URLClassLoader.java:362) at java.security.AccessController.doPrivileged(Native Method) at java.net.URLClassLoader.findClass(URLClassLoader.java:361) at java.lang.ClassLoader.loadClass(ClassLoader.java:424) at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331) at java.lang.ClassLoader.loadClass(ClassLoader.java:357) at org.clapper.classutil.asm.ClassFile$.load(ClassFinderImpl.scala:250) at org.clapper.classutil.ClassFinder.org$clapper$classutil$ClassFinder$$classData(ClassFinder.scala:427) at org.clapper.classutil.ClassFinder$$anonfun$5.apply(ClassFinder.scala:411) at org.clapper.classutil.ClassFinder$$anonfun$5.apply(ClassFinder.scala:409) at scala.collection.immutable.Stream.map(Stream.scala:418) at org.clapper.classutil.ClassFinder.processDirectory(ClassFinder.scala:409) at org.clapper.classutil.ClassFinder.findClassesIn(ClassFinder.scala:333) at org.clapper.classutil.ClassFinder.find(ClassFinder.scala:320) at org.clapper.classutil.ClassFinder.getClasses(ClassFinder.scala:311)

[instanceofme]

This issue seems caused by the presence of ASM 3.x in the classpath, causing a conflict. In this earlier version, ClassVisitor was an interface instead of an abstract class.

The common way to go seems to be shadowing asm, relocating its package to something like org.clapper.classutil.shadow.asm. Do you think that would be possible here?

[bmc]

I'll try that. Thanks.

[instanceofme]

I confirm that this solved at least my instance of this issue. Used jar jar links to relocate inside an assembly (fat / consolidated) jar that had a dependency on classutil, worked like a charm.

[bmc]

I'm not sure (yet) whether I want to shadow ASM in the official released classutil jar, but I can at least provide documentation on getting around the problem. Thanks.