Message Title

Caused by: java.lang.IndexOutOfBoundsException (Index: 0)
    at java.util.Collections$EmptyList.get(Collections.java:4454)
    at org.hibernate.ogm.query.impl.OgmQueryLoader.listOfArrays(OgmQueryLoader.java:110)
    at org.hibernate.ogm.query.impl.OgmQueryLoader.list(OgmQueryLoader.java:73)
    at org.hibernate.loader.hql.QueryLoader.list(QueryLoader.java:501)
    at org.hibernate.ogm.query.impl.OgmQueryTranslator.list(OgmQueryTranslator.java:127)
    at org.hibernate.engine.query.spi.HQLQueryPlan.performList(HQLQueryPlan.java:216)
    at org.hibernate.internal.SessionImpl.list(SessionImpl.java:1326)
    at org.hibernate.internal.QueryImpl.list(QueryImpl.java:87)
    at org.hibernate.jpa.internal.QueryImpl.list(QueryImpl.java:593)
    at org.hibernate.jpa.internal.QueryImpl.getSingleResult(QueryImpl.java:516)
    at ch.sbi.forte.persistence.dao.ProductManager.count(ProductManager.java:152)

Am I right that aggregation operators are currently not supported for MongoDB? If so, could someone outline where I would need to start to implement this. Any hints appreciated.