Thomas Mogwitz ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=6319ba4... ) *created* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiMGMyYjg0ZDBk... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-15602?atlOrigin=eyJpIjoiMGMyYj... ) HHH-15602 ( https://hibernate.atlassian.net/browse/HHH-15602?atlOrigin=eyJpIjoiMGMyYj... ) ByteBuddy enhancement generates faulty code with many-to-many associations ( https://hibernate.atlassian.net/browse/HHH-15602?atlOrigin=eyJpIjoiMGMyYj... ) Issue Type: Bug Affects Versions: 5.3.27, 6.1.4 Assignee: Unassigned Components: bytecode-enhancement Created: 13/Oct/2022 07:30 AM Priority: Minor Reporter: Thomas Mogwitz ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=6319ba4... ) SpotBugs reports a high-prio warning in entity classes that have been enhanced with ByteBuddy enhancement: EC: Using pointer equality to compare different types (EC_UNRELATED_TYPES_USING_POINTER_EQUALITY) ------------------------------------------------------------------------------------------------- This method uses pointer equality to compare two references that seem to be of different types. The result of this comparison will always be false at runtime. The faulty code is in the generated many-to-many handler functions. Here's the relevant part of org.hibernate.bytecode.enhance.internal.bytebuddy.CodeTemplates static class ManyToManyHandler {     (a)Advice.OnMethodEnter     static void enter((a)Advice.This Object self, @FieldValue Collection<?> field, @Advice.Argument(0) Collection<?> argument, @MappedBy String mappedBy) {         if ( field != null && Hibernate.isPropertyInitialized( field, mappedBy ) ) {             Object[] array = field.toArray();             for ( Object array1 : array ) {                 if ( argument == null || !argument.contains( array1 ) ) {                     getter( array1 ).remove( self );                 }             }         }     }       (a)Advice.OnMethodExit     static void exit((a)Advice.This Object self, @Advice.Argument(0) Collection<?> argument, @MappedBy String mappedBy) {         if ( argument != null && Hibernate.isPropertyInitialized( argument, mappedBy ) ) {             Object[] array = argument.toArray();             for ( Object array1 : array ) {                 if ( Hibernate.isPropertyInitialized( array1, mappedBy ) ) {                     Collection<Object> c = getter( array1 );                     if ( c != self && c != null ) { // <- pointer-comparing a collection and an entity object                         c.add( self );                     }                 }             }         }      }       static Collection<Object> getter(Object self) {         // is replaced by the actual method call         throw new AssertionError();     } } I believe that the intended conditions in the if-statement in line 21 should have been: if (c != null && !c.contains(self) ) The bug has been around at least since 5.3.27, probably even eralier, and is still there in the current version. ( https://hibernate.atlassian.net/browse/HHH-15602#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-15602#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100208- sha1:492d0ce )