Eclipselink 2.5.2 JPA NPE querying elementcollection on glassfish 4 - jpa

Question

I'm facing a strange problem porting a working application from JEE6 (glassfish 3/eclipselink 2.5.1) to JEE7 (glassfish 4/eclipselink 2.5.2).
I've these entities (getter/setter are project Lombok annotations):
#Entity
#Table(name = "languages")
public class Language {
#Getter
#Setter
#NotNull
#Column(name = "code")
private String code;
#Getter
#Setter
#ManyToOne(cascade = CascadeType.ALL)
#JoinColumn(name = "translation_id")
private Translation translations = new Translation();
}
#Entity
#Table(name = "translations")
public class Translation {
#ElementCollection
#MapKeyColumn(name="locale")
#Column(name="description")
#CollectionTable(name="translations_values")
private Map<String, String> strings = new HashMap<>();
public Translation() {
}
public Translation(Map<String, String> map) {
this.strings = map;
}
public void setString(String locale, String text) {
strings.put(locale, text);
}
public String getString(String locale) {
String returnValue = strings.get(locale);
return (returnValue != null ? returnValue : null);
}
}
If I run this JPQL query, it works:
select o from Language o join o.translations t join t.strings s where key(s) = 'it' and value(s) = 'Italiano'
If I run the same query adding an order by clause on elementcollection, it doesn't work:
select o from Language o join o.translations t join t.strings s where key(s) = 'it' and value(s) = 'Italiano' order by value(s)
The result is:
Local Exception Stack:
Exception [EclipseLink-6168] (Eclipse Persistence Services - 2.5.1.v20130918-f2b9fc5): org.eclipse.persistence.exceptions.QueryException
Exception Description: Query failed to prepare, unexpected error occurred: [java.lang.NullPointerException].
Internal Exception: java.lang.NullPointerException
Query: ReadAllQuery(referenceClass=Language jpql="select o from Language o join o.translations t join t.strings s where key(s) = 'it' and value(s) = 'Italiano' order by value(s)")
at org.eclipse.persistence.exceptions.QueryException.prepareFailed(QueryException.java:1589)
at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:680)
at org.eclipse.persistence.queries.ObjectLevelReadQuery.checkPrepare(ObjectLevelReadQuery.java:901)
at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:613)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:194)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.buildEJBQLDatabaseQuery(EJBQueryImpl.java:116)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:102)
at org.eclipse.persistence.internal.jpa.EJBQueryImpl.<init>(EJBQueryImpl.java:86)
at org.eclipse.persistence.internal.jpa.EntityManagerImpl.createQuery(EntityManagerImpl.java:1603)
Caused by: java.lang.NullPointerException
at org.eclipse.persistence.mappings.ForeignReferenceMapping.getOrderByNormalizedExpressions(ForeignReferenceMapping.java:2456)
at org.eclipse.persistence.internal.expressions.SQLSelectStatement.normalizeOrderBy(SQLSelectStatement.java:1614)
at org.eclipse.persistence.internal.expressions.SQLSelectStatement.normalize(SQLSelectStatement.java:1403)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.buildNormalSelectStatement(ExpressionQueryMechanism.java:549)
at org.eclipse.persistence.internal.queries.ExpressionQueryMechanism.prepareSelectAllRows(ExpressionQueryMechanism.java:1720)
at org.eclipse.persistence.queries.ReadAllQuery.prepareSelectAllRows(ReadAllQuery.java:813)
at org.eclipse.persistence.queries.ReadAllQuery.prepare(ReadAllQuery.java:744)
at org.eclipse.persistence.queries.DatabaseQuery.checkPrepare(DatabaseQuery.java:661)
... 9 more
My application on glassfish 3 / eclipselink 2.5.1 works fine on the JPQL query above.
Is there any workaround ?
Many thanks in advance