Issue 1815: Transforming object types for collections

Signed-off-by: Will Dazey <dazeydev.3@gmail.com>

foundation/org.eclipse.persistence.core/src/main/java/org/eclipse/persistence/internal/expressions/QueryKeyExpression.java

@@ -21,6 +21,7 @@
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
+import java.util.Collections;
 import java.util.Enumeration;
 import java.util.HashMap;
 import java.util.Iterator;
@@ -34,6 +35,7 @@
 import org.eclipse.persistence.expressions.Expression;
 import org.eclipse.persistence.internal.helper.DatabaseField;
 import org.eclipse.persistence.internal.helper.DatabaseTable;
+import org.eclipse.persistence.internal.helper.Helper;
 import org.eclipse.persistence.internal.identitymaps.CacheId;
 import org.eclipse.persistence.internal.queries.MappedKeyMapContainerPolicy;
 import org.eclipse.persistence.internal.sessions.AbstractRecord;
@@ -424,8 +426,11 @@ public Object getFieldValue(Object objectValue, AbstractSession session) {
         Object fieldValue = objectValue;
         if (mapping != null) {
             if (mapping.isAbstractDirectMapping() || mapping.isDirectCollectionMapping()) {
+
                 // CR#3623207, check for IN Collection here not in mapping.
-                if (objectValue instanceof Collection) {
+                // Translate the individual elements of a collection to match the mapping, but only if the mapping is not to a collection itself
+                Class<?> cls = mapping.getFieldClassification(getField());
+                if (objectValue instanceof Collection && (cls != null && !(cls.isArray() || cls.isInstance(Collection.class)))) {
                     // This can actually be a collection for IN within expressions... however it would be better for expressions to handle this.
                     Collection values = (Collection)objectValue;
                     Vector fieldValues = new Vector(values.size());