| Name | Type | Parent | Since | Detail |
| Optional | Class | java.lang.Object | 1.8 | Link |
| OptionalDataException | Class | java.io.ObjectStreamException | 1.1 | Link |
| OptionalDouble | Class | java.lang.Object | 1.8 | Link |
| OptionalInt | Class | java.lang.Object | 1.8 | Link |
| OptionalLong | Class | java.lang.Object | 1.8 | Link |
