UnsupportedClassVersionError: JVMCFRE003 bad major version in WebSphere AS 7

Question

I am getting this error

java.lang.UnsupportedClassVersionError: JVMCFRE003 bad major version; class=map/CareMonths, offset=6

My Eclipse's Java compiler is set to 1.6 and my installed Java SDK in C:\Program Files is 1.6.0, but still I get this error when I install my app to Webshere Application Server V7.

What does offset=6 mean? I want to compile using Java 6 and Websphere 7 supports Java 6.

I do see that the JDK in the IBM directory where server is installed is Java 7. Is that what is causing this? ....but again my workspace's Eclipse compiler is set to Java 1.6.

Answer 1

WebSphere Application Server V7 does support Java Platform, Standard Edition (Java SE) 6 (see Specifications and API documentation in the Network Deployment (All operating systems), Version 7.0 Information Center) and it's since the release V8.5 when Java 7 has been supported.

I couldn't find the Java 6 SDK documentation, and could only consult IBM JVM Messages in Java 7 Windows documentation. Alas, I couldn't find the error message in the documentation either.

Since java.lang.UnsupportedClassVersionError is "Thrown when the Java Virtual Machine attempts to read a class file and determines that the major and minor version numbers in the file are not supported.", you ran into an issue of building the application with more recent version of Java than the one supported by the runtime environment, i.e. WebSphere Application Server 7.0.

I may be mistaken, but I think that offset=6 in the message is to let you know what position caused the incompatibility issue to occur. It's irrelevant for you, for me, and for many other people, but some might find it useful, esp. when they generate bytecode themselves.

Run the versionInfo command to find out about the Installed Features of WebSphere Application Server V7, e.g.

C:\IBM\WebSphere\AppServer>.\bin\versionInfo.bat
WVER0010I: Copyright (c) IBM Corporation 2002, 2005, 2008; All rights reserved.
WVER0012I: VersionInfo reporter version 1.15.1.47, dated 10/18/11

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IBM WebSphere Product Installation Status Report
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Report at date and time February 19, 2013 8:07:20 AM EST

Installation
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Product Directory        C:\IBM\WebSphere\AppServer
Version Directory        C:\IBM\WebSphere\AppServer\properties\version
DTD Directory            C:\IBM\WebSphere\AppServer\properties\version\dtd
Log Directory            C:\ProgramData\IBM\Installation Manager\logs

Product List
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BPMPC                    installed
ND                       installed
WBM                      installed

Installed Product
--------------------------------------------------------------------------------
Name                  IBM Business Process Manager Advanced V8.0
Version               8.0.1.0
ID                    BPMPC
Build Level           20121102-1733
Build Date            11/2/12
Package               com.ibm.bpm.ADV.V80_8.0.1000.20121102_2136
Architecture          x86-64 (64 bit)
Installed Features    Non-production
                      Business Process Manager Advanced - Client (always installed)
Optional Languages    German
                      Russian
                      Korean
                      Brazilian Portuguese
                      Italian
                      French
                      Hungarian
                      Simplified Chinese
                      Spanish
                      Czech
                      Traditional Chinese
                      Japanese
                      Polish
                      Romanian

Installed Product
--------------------------------------------------------------------------------
Name                  IBM WebSphere Application Server Network Deployment
Version               8.0.0.5
ID                    ND
Build Level           cf051243.01
Build Date            10/22/12
Package               com.ibm.websphere.ND.v80_8.0.5.20121022_1902
Architecture          x86-64 (64 bit)
Installed Features    IBM 64-bit SDK for Java, Version 6
                      EJBDeploy tool for pre-EJB 3.0 modules
                      Embeddable EJB container
                      Sample applications
                      Stand-alone thin clients and resource adapters
Optional Languages    German
                      Russian
                      Korean
                      Brazilian Portuguese
                      Italian
                      French
                      Hungarian
                      Simplified Chinese
                      Spanish
                      Czech
                      Traditional Chinese
                      Japanese
                      Polish
                      Romanian

Installed Product
--------------------------------------------------------------------------------
Name                  IBM Business Monitor
Version               8.0.1.0
ID                    WBM
Build Level           20121102-1733
Build Date            11/2/12
Package               com.ibm.websphere.MON.V80_8.0.1000.20121102_2222
Architecture          x86-64 (64 bit)
Optional Languages    German
                      Russian
                      Korean
                      Brazilian Portuguese
                      Italian
                      French
                      Hungarian
                      Simplified Chinese
                      Spanish
                      Czech
                      Traditional Chinese
                      Japanese
                      Polish
                      Romanian

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End Installation Status Report
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