javax.transaction.Synchronization with Java SE 10.0.1

Greetings,

I am trying to get my app running on Java 10 (up to now it runs on Java 8) and with the latest version of ObjectDB it enhances fine, but during runtime when first trying to instantiate the PersistenceManager, it gives me the following error

java.lang.NoClassDefFoundError: javax/transaction/Synchronization
    at java.base/java.lang.ClassLoader.defineClass1(Native Method)
    at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1009)
    at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174)
    at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:801)
    at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:699)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:622)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:580)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:190)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
    at java.base/java.lang.ClassLoader.defineClass1(Native Method)
    at java.base/java.lang.ClassLoader.defineClass(ClassLoader.java:1009)
    at java.base/java.security.SecureClassLoader.defineClass(SecureClassLoader.java:174)
    at java.base/jdk.internal.loader.BuiltinClassLoader.defineClass(BuiltinClassLoader.java:801)
    at java.base/jdk.internal.loader.BuiltinClassLoader.findClassOnClassPathOrNull(BuiltinClassLoader.java:699)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(BuiltinClassLoader.java:622)
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:580)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:190)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
    at java.base/java.lang.Class.forName0(Native Method)
    at java.base/java.lang.Class.forName(Class.java:374)
    at javax.jdo.JDOHelper$18.run(JDOHelper.java:1944)
    at java.base/java.security.AccessController.doPrivileged(Native Method)
    at javax.jdo.JDOHelper.forName(JDOHelper.java:1941)
    at javax.jdo.JDOHelper.invokeGetPersistenceManagerFactoryOnImplementation(JDOHelper.java:1152)
    at javax.jdo.JDOHelper.getPersistenceManagerFactory(JDOHelper.java:800)
    at javax.jdo.JDOHelper.getPersistenceManagerFactory(JDOHelper.java:715)
    at eu.extech.serverImpl.jdo.JDOConnection.persistenceManagerInit(JDOConnection.java:384)

Caused by: java.lang.ClassNotFoundException: javax.transaction.Synchronization
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:582)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:190)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:499)
    ... 35 more

So a searched for this class in Eclipse and found it only in objectdb.jar, not anymore in JRE (using Java SE 10.0.1). So I tried to track down why it is not found via runtime and discovered that within the method jdk.internal.loader.BuiltinClassLoader.loadClassOrNull(String cn, boolean resolve) there is found a LoadedModule with this footprint

[module java.transaction, location=jrt:/java.transaction]

and within this module the Synchronization class was not found.

If I am not mistaken this module comes from the JRE and not from objectdb.jar, so I thought that's why objectdb.jar is not searched at all for it.

I tried then adding this command line argument to make the JVM search it in objectdb.jar

--patch-module java.transaction=lib/objectdb.jar

But with that the JVM did not start at all and threw the following error

Error occurred during initialization of boot layer
java.lang.LayerInstantiationException: Package javax.transaction.xa in both module java.transaction and module java.sql

Could you please advice me how to make my app locate this class ?

Regards,

Gergely

As you figured out, the issue is with the java.transaction module in JDK 9  / JDK 10, which includes only a small subset of that package and particularly does not include the Synchronization interface.

Are you using -add-modules java.se.ee?

If yes, try removing it. See this thread on Stackoverflow.

I was not using -add-modules java.se.ee, but -add-modules java.corba which turned out to load also the java.transaction module. Once a managed to get rid of -add-modules java.corba , the JVM found the Synchronization interface and ObjectDB was working well.