Request malformed on a left fetch join subItem.myCollection (double outer join) : uncorrect fromElementList, can't find the associated collectionOwner and initialize a proxy on an empty fetched collection ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- Key: HHH-6518 URL: http://opensource.atlassian.com/projects/hibernate/browse/HHH-6518 Project: Hibernate Core Issue Type: Bug Components: core, query-sql Affects Versions: 3.6.6, 4.0.0.Beta4 Reporter: Quentin Ambard Labels: HQL, Parser, proxy Attachments: CORRECThibernateTestCase.tar.gz, hibernateTestCase.tar.gz There is an error fetching a collection of a subitem. This affect empty collections : a proxy is intialized on the collection, even fetched. Accessing to this collection fire a new request. Here is a simple mode. Please see test case for complete implementation: @Entity @Table( name = "ITEM" ) public class Item { @Id @GeneratedValue private Long id; @OneToOne(cascade = { CascadeType.ALL }, optional = true, fetch = FetchType.LAZY, orphanRemoval = true) @JoinColumn(name = "SUB_ITEM_ID") private SubItem subItem ; ... } public class SubItem { @Id @GeneratedValue private Long id; @ElementCollection(targetClass = String.class, fetch = FetchType.LAZY) @CollectionTable(name = "PHONES") @Column(name = "PHONE", nullable = false) private List<String> phones ; ... } the following hql request "from Item i left join fetch i.subItem left join fetch i.subItem.phones" generates this sql request : select item0_.id as id2_0_, subitem1_.id as id1_1_, item0_.SUB_ITEM_ID as SUB2_2_0_, phones3_.SubItem_id as SubItem1_1_0__, phones3_.PHONE as PHONE0__, phones3_.SubItem_id as SubItem1_1_0__, phones3_.PHONE as PHONE0__ from ITEM item0_ left outer join SUB_ITEM subitem1_ on item0_.SUB_ITEM_ID=subitem1_.id left outer join SUB_ITEM subitem2_ on item0_.SUB_ITEM_ID=subitem2_.id left outer join PHONES phones3_ on subitem2_.id=phones3_.SubItem_id There is an extra left outerjoin. QueryClassLoader.initialize(SelectClause selectClause) can't find the collectionOwner for the PHONES collection : collectionFromElement.getOrigin()is about the second left outer join : "SUB_ITEM subitem2_ on item0_.SUB_ITEM_ID=subitem2_.id" and the fromElementList is based on the first outer join "subitem1_ on item0_.SUB_ITEM_ID=subitem1_.id". The following hql request doesn't work either : from Item i left join fetch i.subItem s left join fetch s.phones Request is correctly generated, but the left outer join collectionPersisters is null java.lang.NullPointerException at org.hibernate.loader.BasicLoader.isBag(BasicLoader.java:97) at org.hibernate.loader.BasicLoader.postInstantiate(BasicLoader.java:76) at org.hibernate.loader.hql.QueryLoader.<init>(QueryLoader.java:120) at org.hibernate.hql.internal.ast.QueryTranslatorImpl.doCompile(QueryTranslatorImpl.java:204) ... see attached test case for full stack