I have a project that produces "cite/käyttötapakuvaus.html" as an artifact. With compress-artifacts-plugin 1.10 installed, the resulting archive.zip has the following file header in its central directory:

• central file header signature: 50 4B 01 02
• version made by: 3F 00, i.e. spec v6.3
• version needed to extract: 14 00, i.e. spec v2.0
• general purpose bit flag: 08 00, i.e. the file name is not claimed to be UTF-8
• compression method: 08 00
• last mod file time: 0D A7
• last mod file date: 88 4B
• crc-32: D2 3A 07 C1
• compressed size: 05 07 00 00
• uncompressed size: DF 17 00 00
• file name length: 1A 00
• extra field length: 00 00, i.e. no alternative file name is stored in the extra field
• file comment length: 00 00
• disk number start: 00 00
• internal file attributes: 00 00
• external file attributes: 00 00 00 00
• relative offset of local header: 2E 90 03 00
• file name: 63 69 74 65 2F 6B E4 79 74 74 F6 74 61 70 61 6B 75 76 61 75 73 2E 68 74 6D 6C, i.e. "ä" was encoded as 0xE4, and "ö" was encoded as 0xF6. This matches Latin-1 and Windows-1252, but not CP437 nor UTF-8.

However, when I view the artifacts listing in Jenkins, it includes a link <a href="k%EF%BF%BDytt%EF%BF%BDtapakuvaus.html">k�ytt�tapakuvaus.html</a>, i.e. the non-ASCII characters have been replaced with U+FFFD REPLACEMENT CHARACTER. This link actually works, but it looks very ugly. Other HTML artifacts contain links like <a href="k%C3%A4ytt%C3%B6tapakuvaus.html">käyttötapakuvaus</a>, and those links do not work.

If I understand correctly, the file names in archive.zip should not be Latin-1 at all. APPNOTE.TXT - .ZIP File Format Specification v6.3.4 says they should be CP437 by default, or UTF-8 if bit 11 of the general purpose bit flag is set. However, TrueZipArchiver.java does zip = new ZipOutputStream(out, Charset.defaultCharset()), and I suppose the default charset is Windows-1252 here.

I'm not sure which charset ZipFile expects when ZipStorage.java constructs it as new ZipFile(archive); the javadocs used to be at java.net, which has been shut down. RawZipFile.DEFAULT_CHARSET suggests it may be expecting UTF-8.

Because the archive.zip files are intended to be read back by the compress-artifacts-plugin itself rather than published as is, I think it would be best to hardcode UTF-8 in TrueZipArchiver.java.