Branch: refs/heads/5.3 Home: https://github.com/hibernate/hibernate-orm Commit: 86d883e998651585062e819ed4d29589fe638261 https://github.com/hibernate/hibernate-orm/commit/86d883e998651585062e819... Author: Yoann Rodière <yoann(a)hibernate.org&gt; Date: 2021-06-04 (Fri, 04 Jun 2021) Changed paths: M hibernate-core/src/test/java/org/hibernate/test/bytecode/enhancement/lazy/NaturalIdInUninitializedAssociationTest.java Log Message: ----------- HHH-13682 Enable extended bytecode enhancement in NaturalIdInUninitializedAssociationTest This test accesses a field of an entity directly and expects it to be automatically initialized; this cannot work without extended bytecode enhancement. This used to work with Java 8 bytecode, but only by chance. It seems that Java 8 bytecode relies on "synthetic", static access methods inserted by the compiler to access the fields of entities in this test: any access to the field is done through this access method instead of through a direct field access. Since we apply bytecode enhancement to all methods of entities, this means that access to fields triggers initialization, without any bytecode enhancement in the caller class. I believe this is specific to nested classes, but couldn't find a source. For reference, the bytecode of access methods looks like this: static int access$002(org.hibernate.test.bytecode.enhancement.lazy.NaturalIdInUninitializedAssociationTest$AnEntity, int); Code: 0: aload_0 1: iload_1 2: dup_x1 3: putfield #3 // Field id:I 6: ireturn static org.hibernate.test.bytecode.enhancement.lazy.NaturalIdInUninitializedAssociationTest$EntityImmutableNaturalId access$102(org.hibernate.test.bytecode.enhancement.lazy.NaturalIdInUninitializedAssociationTest$AnEntity, org.hibernate.test.bytecode.enhancement.lazy.NaturalIdInUninitializedAssociationTest$EntityImmutableNaturalId); Code: 0: aload_0 1: aload_1 2: dup_x1 3: putfield #2 // Field entityImmutableNaturalId:Lorg/hibernate/test/bytecode/enhancement/lazy/NaturalIdInUninitializedAssociationTest$EntityImmutableNaturalId; 6: areturn With Java 11, however, access to fields of entities is done directly, even for nested classes. So the access methods no longer exist, and we don't get automatic initialization upon field access. We need extended bytecode enhancement, like we would in any other case of field access (in particular accessing fields of non-nested classes). (cherry picked from commit 1060baf74b3d480d026a3d88e9c4b2d4aae118a3)