Description of problem:
When running the migration tool in standard way, on some machines the migration ends with CCE: org.drools.compiler.rule.builder.dialect.mvel.lMVELDialectConfiguration cannot be cast to org.drools.compiler.DialectConfiguration.

Unfortunately its not happening on all machines (its classpath order related issue), so it might be very hard to reproduce. However in our environment 2 out of 3 machines experienced the problem.

I suspect its classpath order related issue. The migration tool needs both drool5 and drool6 jars on CP and thus file 'packagebuilder.conf' will end up on classpath twice (its in drools-compiler-6.0.0.Beta5.jar and guvnor-jcr2vfs-migration-droolsjbpm-as-uberjar-5.5.1-20130606.153149-125-jars-as-uberjar.jar). The file contains dialect definitions class names. There are two possible cases:

  1) drools-compiler-6.0.0.Beta5.jar/META-INF/packagebuilder.conf is loaded and because it contains drools6 class names the drools5 PackageBuilderConfiguration won't be able to cast it. And thus the mentioned CCE will be thrown.

  2) guvnor-jcr2vfs-migration-droolsjbpm-as-uberjar-5.5.1-20130606.153149-125-jars-as-uberjar.jar/META-INF/packagebuilder.conf is loaded and everything goes as expected because the drools5 class names will be used.

Removing the drools-compiler-6.0.0.Beta5.jar/META-INF/packagebuilder.conf __seems__ to solve the problem, however it could cause other issues.


Full stacktrace:
Exception in thread "main" org.drools.RuntimeDroolsException: Unable to load dialect 'org.drools.compiler.rule.builder.dialect.mvel.MVELDialectConfiguration:mvel:org.drools.compiler.rule.builder.dialect.mvel.MVELDialectConfiguration'
	at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:321)
	at org.drools.compiler.PackageBuilderConfiguration.buildDialectConfigurationMap(PackageBuilderConfiguration.java:307)
	at org.drools.compiler.PackageBuilderConfiguration.init(PackageBuilderConfiguration.java:192)
	at org.drools.compiler.PackageBuilderConfiguration.<init>(PackageBuilderConfiguration.java:165)
	at org.drools.guvnor.server.builder.BRMSPackageBuilder.getPackageBuilderConfiguration(BRMSPackageBuilder.java:134)
	at org.drools.guvnor.server.builder.BRMSPackageBuilder.<init>(BRMSPackageBuilder.java:67)
	at org.drools.workbench.jcr2vfsmigration.migrater.asset.GuidedEditorMigrater.migrate(GuidedEditorMigrater.java:96)
	at org.drools.workbench.jcr2vfsmigration.migrater.asset.GuidedEditorMigrater$Proxy$_$$_WeldClientProxy.migrate(GuidedEditorMigrater$Proxy$_$$_WeldClientProxy.java)
	at org.drools.workbench.jcr2vfsmigration.migrater.AssetMigrater.migrate(AssetMigrater.java:159)
	at org.drools.workbench.jcr2vfsmigration.migrater.AssetMigrater.migrateAll(AssetMigrater.java:135)
	at org.drools.workbench.jcr2vfsmigration.migrater.AssetMigrater$Proxy$_$$_WeldClientProxy.migrateAll(AssetMigrater$Proxy$_$$_WeldClientProxy.java)
	at org.drools.workbench.jcr2vfsmigration.Jcr2VfsMigrater.migrateAll(Jcr2VfsMigrater.java:82)
	at org.drools.workbench.jcr2vfsmigration.Jcr2VfsMigrater$Proxy$_$$_WeldClientProxy.migrateAll(Jcr2VfsMigrater$Proxy$_$$_WeldClientProxy.java)
	at org.drools.workbench.jcr2vfsmigration.Jcr2VfsMigrationApp.main(Jcr2VfsMigrationApp.java:36)
Caused by: java.lang.ClassCastException: org.drools.compiler.rule.builder.dialect.mvel.lMVELDialectConfiguration cannot be cast to org.drools.compiler.DialectConfiguration
	at org.drools.compiler.PackageBuilderConfiguration.addDialect(PackageBuilderConfiguration.java:316)
	... 13 more


Version-Release number of selected component (if applicable):
6.0.0-DR6


Steps to Reproduce:
1. Just run the migration tool in standard way (however the issue will not be present on all machines).


Actual results:
On some machines the migration tool throws CCE.


Expected results:
The CCE is never thrown.