Compress4J reads, but cannot write, some formats. Archives have an extractor only; codecs have a Compression value that Decompressor and the tar extractor read and Compressor rejects.

Convention

  • An archive has no creator class; a codec’s Compression.canWrite() returns false.

  • The format’s page opens with the note Read-only: Compress4J can extract this format but cannot create it.

  • Format lists mark the format with (read-only).

  • Extractors enforce the same guards as every other archive extractor: path traversal, escaping symlink policy, and entry and size limits.

Read-only formats

Format How to read it

ARJ

ArjArchiveExtractor

UNIX dump

DumpArchiveExtractor

Deflate64

Compression.deflate64() with Decompressor; see Deflate64

Brotli

Compression.brotli() with Decompressor; needs org.brotli:dec, see Brotli

Unix compress (.Z)

Compression.unixZ() with Decompressor, detected automatically; .tar.Z through TarArchiveExtractor; see Unix compress

The codec table marks every read-only codec.