The JPA Spec. Version 2.0 states in chapter 2.1 that "The entity class must have a no-arg constructor. The entity class may have other constructors as well.
The no-arg constructor must be public or protected." And in chapter 2.5 it says that the same is true for embeddable classes. However in line 56 of class AbstractCompositeIdMapper you assume that constructors of embeddable classes are always public.

Stacktrace:

org.hibernate.envers.exception.AuditException: java.lang.IllegalAccessException: Class org.hibernate.envers.entities.mapper.id.AbstractCompositeIdMapper can not access a member of class foo.EmbeddedId with modifiers "protected"
at org.hibernate.envers.entities.mapper.id.AbstractCompositeIdMapper.mapToIdFromMap(AbstractCompositeIdMapper.java:58)
at org.hibernate.envers.entities.mapper.relation.ToOneIdMapper.nullSafeMapToEntityFromMap(ToOneIdMapper.java:91)
at org.hibernate.envers.entities.mapper.relation.AbstractToOneMapper.mapToEntityFromMap(AbstractToOneMapper.java:38)
at org.hibernate.envers.entities.mapper.MultiPropertyMapper.mapToEntityFromMap(MultiPropertyMapper.java:137)
at org.hibernate.envers.entities.EntityInstantiator.createInstanceFromVersionsEntity(EntityInstantiator.java:110)
at org.hibernate.envers.entities.EntityInstantiator.addInstancesFromVersionsEntities(EntityInstantiator.java:142)
at org.hibernate.envers.query.impl.EntitiesAtRevisionQuery.list(EntitiesAtRevisionQuery.java:114)
at org.hibernate.envers.query.impl.AbstractAuditQuery.getResultList(AbstractAuditQuery.java:105)
at a service...
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:28)
at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:31)
at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:71)
at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:199)
at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:62)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: java.lang.IllegalAccessException: Class org.hibernate.envers.entities.mapper.id.AbstractCompositeIdMapper can not access a member of class foo.EmbeddedId with modifiers "protected"
at sun.reflect.Reflection.ensureMemberAccess(Reflection.java:65)
at java.lang.Class.newInstance0(Class.java:349)
at java.lang.Class.newInstance(Class.java:308)
at org.hibernate.envers.entities.mapper.id.AbstractCompositeIdMapper.mapToIdFromMap(AbstractCompositeIdMapper.java:56)
... 36 more