Hibernate Search (main) has several Service Provider implementations defined via the META-INF/services/StandardServiceManager mechanism. 

One of these services is the JGroupsChannelProvider implementation which requires JGroups to be available in the classpath.

However, since the system/layers/base/org/hibernate/search/engine/main/module.xml file does not list "org.jgroups" as a dependency, the following exception can occur:

Caused by: java.lang.NoClassDefFoundError: org/jgroups/MessageListener
       at java.lang.Class.forName0(Native Method) [rt.jar:1.7.0_40]
       at java.lang.Class.forName(Class.java:270) [rt.jar:1.7.0_40]
       at org.hibernate.search.util.impl.ClassLoaderHelper.classForName(ClassLoaderHelper.java:315)
       at org.hibernate.search.util.impl.ClassLoaderHelper.classForName(ClassLoaderHelper.java:282)
       at org.hibernate.search.engine.impl.StandardServiceManager.listAndInstantiateServiceProviders(StandardServiceManager.java:82)
       at org.hibernate.search.engine.impl.StandardServiceManager.<init>(StandardServiceManager.java:65)
       at org.hibernate.search.spi.SearchFactoryBuilder.createCleanFactoryState(SearchFactoryBuilder.java:296)
       at org.hibernate.search.spi.SearchFactoryBuilder.buildNewSearchFactory(SearchFactoryBuilder.java:204)
       at org.hibernate.search.spi.SearchFactoryBuilder.buildSearchFactory(SearchFactoryBuilder.java:143)
       at org.modeshape.jcr.RepositoryQueryManager.queryEngine(RepositoryQueryManager.java:185)
       at org.modeshape.jcr.RepositoryQueryManager.getIndexes(RepositoryQueryManager.java:171)
       at org.modeshape.jcr.RepositoryQueryManager.indexesEmpty(RepositoryQueryManager.java:233)
       at org.modeshape.jcr.RepositoryQueryManager.reindexContent(RepositoryQueryManager.java:213)
       at org.modeshape.jcr.JcrRepository$RunningState.postInitialize(JcrRepository.java:1331)
       at org.modeshape.jcr.JcrRepository.doStart(JcrRepository.java:409)
       at org.modeshape.jcr.JcrRepository.login(JcrRepository.java:654)
Caused by: java.lang.ClassNotFoundException: org.jgroups.MessageListener from [Module "org.hibernate.search.engine:main" from local module loader @3cbd9256 (finder: local module finder @41d26b41 (root
s: D:\Work\dv\6.2.0-ER2\modules,D:\Work\dv\6.2.0-ER2\modules\system\layers\dv,D:\Work\dv\6.2.0-ER2\modules\system\layers\base))]
        at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:213) [jboss-modules.jar:1.3.6.Final-redhat-1]
        at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:459) [jboss-modules.jar:1.3.6.Final-redhat-1]
        at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:408) [jboss-modules.jar:1.3.6.Final-redhat-1]
        at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:389) [jboss-modules.jar:1.3.6.Final-redhat-1]
        at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:134) [jboss-modules.jar:1.3.6.Final-redhat-1]
        ... 37 more

This blocks atm. a Teiid - ModeShape integration use case in JDV 6.2.0.