Java: JVMCFRE003 bad major version; class=org/apache/commons/io/FilenameUtils, offset=6

Question

Here's the full error:

Exception in thread "main" java.lang.UnsupportedClassVersionError: JVMCFRE003 bad major version; class=org/apache/commons/io/FilenameUtils, offset=6
    at java.lang.ClassLoader.defineClass(ClassLoader.java:275)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:69)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:540)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:451)
    at java.net.URLClassLoader.access$300(URLClassLoader.java:79)
    at java.net.URLClassLoader$ClassFinder.run(URLClassLoader.java:1038)
    at java.security.AccessController.doPrivileged(AccessController.java:284)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:429)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:660)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:358)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:626)
......

I know it's very common error, but i wouldn't post a question here without spending at least 72 hours trying to fix my issue :). I know why this error appears (I just fixed a bunch of these by compiling with the correct bytecode version), but this is the one last bugger i can't get rid of. So my Java version is as below (yeah i know, old, but organization restrictions ... :p).

java version "1.6.0"
Java(TM) SE Runtime Environment (build pap6460sr9fp2-20110627_03(SR9 FP2))
IBM J9 VM (build 2.4, JRE 1.6.0 IBM J9 2.4 AIX ppc64-64 jvmap6460sr9-
20110624_85526 (JIT enabled, AOT enabled)
J9VM - 20110624_085526
JIT  - r9_20101028_17488ifx17
GC   - 20101027_AA)
JCL  - 20110530_01

The surprising part is that I get this error even with FileNameUtils 2.2 which is compatible with JDK 1.5!

I'm using IntelliJ to compile. These are the places where I set my target bytecode version to 1.5:

1. File -> Project Structure -> Modules :: Sources (next to Paths and Dependencies)--> Language Level 5
2. File -> Settings -> Build, Execution, Deployment -> Compiler -> Java Compiler -> Project Bytecode version: 1.5
3. Project iml file - JDK 1_5
4. Maven compiler version - 1.5

I'm at a total loss comprehending why FileNameUtils 2.2 (and even 1.6) would throw a bad major version error when my bytecode version is one whole level lower than the 1.6 that runs the code.

I've tried Build, Rebuild and Re-import Maven Dependencies too! I hope someone can help me fix the issue.

Answer 1

Here's what worked for me. My artifact configuration in IntelliJ was still pulling newer dependency versions that i had used earlier. I realized i needed to downgrade the versions of some dependencies so i updated my pom.xml. Somehow the artifact did not have the refreshed dependency versions on compiling.

I removed the existing artifact from my IntelliJ config and executed a maven goal this time. This helped pull the correct versions of all dependencies.