Revert "Fix eclipse-ee4j#1161: Clone appropriate fields in OneToManyM…

…apping.clone(). Fix ConcurrentModificationException. (backport for 2.7) (eclipse-ee4j#1208)"

This reverts commit 474f855.

foundation/org.eclipse.persistence.core/src/org/eclipse/persistence/descriptors/ClassDescriptor.java

@@ -1,6 +1,6 @@
 /*
- * Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 1998, 2021 IBM Corporation. All rights reserved.
+ * Copyright (c) 1998, 2020 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2020 IBM Corporation. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -1369,7 +1369,7 @@ public Object clone() {
         clonedDescriptor.setFields(NonSynchronizedVector.newInstance());
 
         // Referencing classes
-        clonedDescriptor.referencingClasses = new HashSet<>(referencingClasses);
+        referencingClasses = new HashSet<>();
 
         // Post-calculate changes
         if (this.mappingsPostCalculateChanges != null) {

foundation/org.eclipse.persistence.core/src/org/eclipse/persistence/mappings/OneToManyMapping.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1998, 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1998, 2018 Oracle and/or its affiliates. All rights reserved.
  *
  * This program and the accompanying materials are made available under the
  * terms of the Eclipse Public License v. 2.0 which is available at
@@ -309,12 +309,7 @@ public void collectQueryParameters(Set<DatabaseField> cacheFields){
     @Override
     public Object clone() {
         OneToManyMapping clone = (OneToManyMapping)super.clone();
-
-        Map<DatabaseField, DatabaseField> old2cloned = new HashMap<>();
-        clone.sourceKeyFields = cloneDatabaseFieldVector(sourceKeyFields, old2cloned);
-        clone.targetForeignKeyFields = cloneDatabaseFieldVector(targetForeignKeyFields, old2cloned);
-        clone.setTargetForeignKeysToSourceKeys(cloneKeysMap(getTargetForeignKeysToSourceKeys(), old2cloned));
-        clone.sourceKeysToTargetForeignKeys = cloneKeysMap(getSourceKeysToTargetForeignKeys(), old2cloned);
+        clone.setTargetForeignKeysToSourceKeys(new HashMap(getTargetForeignKeysToSourceKeys()));
 
         if (addTargetQuery != null){
             clone.addTargetQuery = (DataModifyQuery) this.addTargetQuery.clone();
@@ -325,33 +320,6 @@ public Object clone() {
         return clone;
     }
 
-    private Map<DatabaseField, DatabaseField> cloneKeysMap(Map<DatabaseField, DatabaseField> toClone,
-                                                           Map<DatabaseField, DatabaseField> old2cloned) {
-        if (toClone == null) {
-            return null;
-        }
-        Map<DatabaseField, DatabaseField> cloneTarget2Src = new HashMap<>(toClone.size());
-        for (Map.Entry<DatabaseField, DatabaseField> e : toClone.entrySet()) {
-            cloneTarget2Src.put(old2cloned.get(e.getKey()), old2cloned.get(e.getValue()));
-        }
-        return cloneTarget2Src;
-    }
-
-    private Vector<DatabaseField> cloneDatabaseFieldVector(Vector<DatabaseField> oldFlds,
-                                                           Map<DatabaseField, DatabaseField> old2cloned) {
-        Vector<DatabaseField> clonedSourceKeyFields = null;
-        if (oldFlds != null) {
-            clonedSourceKeyFields =
-                    org.eclipse.persistence.internal.helper.NonSynchronizedVector.newInstance(oldFlds.size());
-            for (DatabaseField old : oldFlds) {
-                DatabaseField cf = old.clone();
-                clonedSourceKeyFields.add(cf);
-                old2cloned.put(old, cf);
-            }
-        }
-        return clonedSourceKeyFields;
-    }
-
     /**
      * INTERNAL
      * Called when a DatabaseMapping is used to map the key in a collection.  Returns the key.