[OPENJPA-1410] Class linkage exception when creating an EMF with OpenJPA M3

• Type: Bug
• Status: Closed
• Priority: Critical
• Resolution: Fixed
• Affects Version/s: 2.0.0-M3, 2.0.0-beta, 2.0.0-beta2
• Fix Version/s: 2.0.0-beta3
• Component/s: validation
• Environment: Tomcat and Glassfish, OpenJPA M3
• Assignee: Jeremy Bauer
• Reporter: Jeremy Bauer
• Created: 02/Dec/09 18:13
• Updated: 12/Apr/11 07:40
• Resolved: 22/Mar/10 12:41

Description

Posted by Seth Jackson on the user forum[1].

It appears something was modified in OpenJPA 2.0 M3 from M2 that causes a
LinkageError.

In my current environment, I've tested both Glassfish and Tomcat using M2
and M3. M2 runs without problems, but M3 throws a linkage error as follows:

Caused by: java.lang.LinkageError: loader constraint violation: loader
(instance of sun/misc/Launcher$AppClassLoader) previously initiated loading
for a different type with name
"org/apache/openjpa/conf/OpenJPAConfiguration"
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:621)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:124)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:260)
at java.net.URLClassLoader.access$000(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:307)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:301)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:320)
at
org.apache.openjpa.persistence.validation.ValidationUtils.setupValidation(ValidationUtils.java:53)
at
org.apache.openjpa.persistence.PersistenceProviderImpl.loadValidator(PersistenceProviderImpl.java:290)
at
org.apache.openjpa.persistence.PersistenceProviderImpl.createEntityManagerFactory(PersistenceProviderImpl.java:97)
at
org.apache.openjpa.persistence.OpenJPAPersistence.createEntityManagerFactory(OpenJPAPersistence.java:128)
at
org.apache.openjpa.persistence.OpenJPAPersistence.createEntityManagerFactory(OpenJPAPersistence.java:111)
at test_test.user.UserAction.execute(UserAction.java:39)

I've already confirmed that the OpenJPA classes in question do NOT exist in
any other JARs in the path.

ValidationUtils.setupValidation(ValidationUtils.java:53) calls the
OpenJPAConfiguration.getConfigurationLog(). The object being referenced is
JDBCConfigurationImpl, which in other classes retrieves the log reference
perfectly fine, before it gets to the offending line.

Seth's follow up[2]:

After further review, using Glassfish 2.1.1 I received this error message in
the server log:

Caused by: java.lang.LinkageError: loader constraint violation: when
resolving method
"org.apache.openjpa.persistence.validation.ValidationUtils.setupValidation(Lorg/apache/openjpa/conf/OpenJPAConfiguration;)Z"
the class loader (instance of org/apache/catalina/loader/WebappClassLoader)
of the current class,
org/apache/openjpa/persistence/PersistenceProviderImpl, and the class loader
(instance of sun/misc/Launcher$AppClassLoader) for resolved class,
org/apache/openjpa/persistence/validation/ValidationUtils, have different
Class objects for the type org/apache/openjpa/conf/OpenJPAConfiguration used
in the signature

So it appears to be the WebappClassLoader and the AppClassLoader are both
loading the OpenJPAConfiguration from the same JAR file, causing the error
when the class is trying to be resolved in this particular method.

[1] http://n2.nabble.com/Struts-2x-OpenJPA-2-0-M3-Tomcat-or-Glassfish-tp4087312p4087312.html
[2] http://n2.nabble.com/Struts-2x-OpenJPA-2-0-M3-Tomcat-or-Glassfish-tp4087312p4093228.html

Issue Links

• is related to: OPENJPA-1976 EntityManager.find method cause errors
• relates to: OPENJPA-1590 Agent enhancer doesn't work with Tomcat
• relates to: OPENJPA-640 ClassNotFoundException for InstrumentationFactory upon startup