| Name | Type | Package | Detail |
| AsyncCallback | Interface | gwt.user.client.rpc | Detail |
| Callback | Interface | gwt.core.client | Detail |
| RequestCallback | Interface | gwt.http.client | Detail |
| ResourceCallback | Interface | gwt.resources.client | Detail |
| RunAsyncCallback | Interface | gwt.core.client | Detail |
| TextResourceCallback | Interface | gwt.resources.client | Detail |
