Hi all, [JEP 408](https://openjdk.org/jeps/408) introduced the Simple Web Server in Java 18, providing a minimal webserver for serving static files over HTTP.
[RFC 9110](https://www.rfc-editor.org/rfc/rfc9110.html#name-range-requests) defines "Range Requests" as an optional feature that allows clients to request a subset of a resource's content. Supporting Range requests in the context of JDK's Simple Web Server means enabling the server to serve only the requested portion of a static file. This change contains: 1. Enhances `sun.net.httpserver.simpleserver.FileServerHandler` in the `jdk.httpserver` module to support `Range` and `If-Range` headers. 2. Calculates an `ETag` for each resource based on its last-modified date and file size and sends it to the client on demand for use with the `If-Range` header. 3. Returns the `Accept-Ranges` header for all file retrievals, and `Content-Range` when a client requests a specific range. 4. Adds a new constant `HTTP_RANGE_NOT_SATISFIABLE` to the `Codes` class to indicate invalid ranges. 5. Returns `206 Partial Content` for valid ranges and `416 Range Not Satisfiable` for invalid ranges. 6. Includes corresponding tests to verify correct behavior. This enhancement was motivated by recent discussions on the net-dev mailing list, which requested support for Range requests along with example use cases: https://mail.openjdk.org/pipermail/net-dev/2025-April/026364.html It was also discussed briefly on the net-dev mailing list: https://mail.openjdk.org/pipermail/net-dev/2025-October/028586.html ------------- Commit messages: - Fix HTTP Range header handling by validating end range and updating test cases - Fix ETag generation by removing weak validator prefix - Implement ETag and If-Range support - Change the content of the test file due to easier understanding - Adding test for ETag and If-Range header support - 8355572: Implement HTTP Range header support in FileServerHandler.serveFile() - Add tests for FileServerHandler - Add HTTP_RANGE_NOT_SATISFIABLE(416) to HTTP response code constants Changes: https://git.openjdk.org/jdk/pull/28021/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28021&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8355572 Stats: 353 lines in 3 files changed: 345 ins; 5 del; 3 mod Patch: https://git.openjdk.org/jdk/pull/28021.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/28021/head:pull/28021 PR: https://git.openjdk.org/jdk/pull/28021
