take element/key/value objects into account for the best possible type descriptor

org.springframework.beans/src/main/java/org/springframework/beans/TypeConverterDelegate.java

@@ -529,7 +529,7 @@ class TypeConverterDelegate {
 				methodParam.increaseNestingLevel();
 			}
 			Object convertedElement = convertIfNecessary(
-					indexedPropertyName, null, element, elementType, typeDescriptor.getElementTypeDescriptor());
+					indexedPropertyName, null, element, elementType, typeDescriptor.getElementTypeDescriptor(element));
 			if (methodParam != null) {
 				methodParam.decreaseNestingLevel();
 			}
@@ -624,12 +624,12 @@ class TypeConverterDelegate {
 				methodParam.setTypeIndexForCurrentLevel(0);
 			}
 			Object convertedKey = convertIfNecessary(keyedPropertyName, null, key, keyType,
-					typeDescriptor.getMapKeyTypeDescriptor());
+					typeDescriptor.getMapKeyTypeDescriptor(key));
 			if (methodParam != null) {
 				methodParam.setTypeIndexForCurrentLevel(1);
 			}
 			Object convertedValue = convertIfNecessary(keyedPropertyName, null, value, valueType,
-					typeDescriptor.getMapValueTypeDescriptor());
+					typeDescriptor.getMapValueTypeDescriptor(value));
 			if (methodParam != null) {
 				methodParam.decreaseNestingLevel();
 			}

org.springframework.core/src/main/java/org/springframework/core/convert/TypeDescriptor.java

@@ -324,7 +324,7 @@ public class TypeDescriptor {
 	 */
 	public TypeDescriptor getMapKeyTypeDescriptor(Object key) {
 		TypeDescriptor keyType = getMapKeyTypeDescriptor();
-		return (keyType != TypeDescriptor.UNKNOWN ? keyType : TypeDescriptor.forObject(key));
+		return (!TypeDescriptor.UNKNOWN.equals(keyType) ? keyType : TypeDescriptor.forObject(key));
 	}
 
 	/**
@@ -353,7 +353,7 @@ public class TypeDescriptor {
 	 */
 	public TypeDescriptor getMapValueTypeDescriptor(Object value) {
 		TypeDescriptor valueType = getMapValueTypeDescriptor();
-		return (valueType != TypeDescriptor.UNKNOWN ? valueType : TypeDescriptor.forObject(value));
+		return (!TypeDescriptor.UNKNOWN.equals(valueType) ? valueType : TypeDescriptor.forObject(value));
 	}
 
 	/**