This page lists the known limitations and problems of Apache
Commons Compress™ grouped by the archiving/compression
format they apply to.
7Z
- the format requires the otherwise optional XZ for Java
library.
- only Files are supported as input/output,
not streams. Starting with Compress 1.13
SeekableByteChannel is supported as well.
- In Compress 1.7
ArchiveStreamFactory will not auto-detect 7z
archives, starting with 1.8 it will throw a
StreamingNotSupportedException when reading from
a 7z archive.
- Encryption, solid compression and header compression and
are only supported when reading archives
- Commons Compress 1.12 and earlier didn't support writing
LZMA.
- Several of the "methods" supported by 7z are not
implemented in Compress.
- No support for multi-volume archives
- Support for some BCJ filters and the DELTA filter has
been added with Compress 1.8. Because of a known bug in
version 1.4 of the XZ for Java
library, archives using BCJ filters will cause an
AssertionError when read. If you need support
for BCJ filters you must use XZ for Java 1.5 or later.
AR
- AR archives can not contain directories - this is a
limitation of the format rather than one of Compress'
implementation.
- file names longer than 16 characters are only fully
supported using the BSD dialect, the GNU/SRV4 dialect is only
supported when reading archives.
ARJ
- read-only support
- no support for compression, encryption or multi-volume
archives
BZIP2
Versions of Compress prior to 1.4.1 are vulnerable to a
possible denial of service attack, see the Security Reports page for details.
CPIO
We are not aware of any problems.
DEFLATE
- CompressorStreamFactory is not able to auto-detect
streams using DEFLATE compression.
DUMP
- read-only support
- only the new-fs format is supported
- the only compression algorithm supported is zlib
GZIP
We are not aware of any problems.
JAR
JAR archives are special ZIP archives, all limitations of ZIP apply to JAR as well.
- ArchiveStreamFactory cannot tell JAR
archives from ZIP archives and will not auto-detect
JARs.
- Compress doesn't provide special access to the archive's
MANIFEST
LZMA
- the format requires the otherwise optional XZ for Java
library.
- Commons Compress 1.12 and earlier only support reading
the format
PACK200
We are not aware of any problems.
TAR
- sparse files can neither be read nor written
- only a subset of the GNU and POSIX extensions are
supported
- In Compress 1.6 TarArchiveInputStream could
fail to read the full contents of an entry unless the stream
was wrapped in a bufferng stream.
XZ
- the format requires the otherwise optional XZ for Java
library.
Z
- Prior to Compress 1.8.1
CompressorStreamFactory was not able to
auto-detect streams using .Z compression.
- read-only support
ZIP
- ZipArchiveInputStream is limited and may
even return false contents in some cases, use
ZipFile whenever possible. See the ZIP
documentation page for details. This limitation is a
result of streaming data vs using random access and not a
limitation of Compress' specific implementation.
- only a subset of compression methods are supported,
including the most common STORED and DEFLATEd. IMPLODE,
SHRINK and BZIP2 support is read-only.
- no support for encryption or multi-volume archives
- In versions prior to Compress 1.6
ZipArchiveEntries read from an archive will
contain non-zero millisecond values when using Java8 rather
than the expected two-second granularity.
- Compress 1.7 has a known bug where the very first entry
of an archive will not be read correctly by
ZipArchiveInputStream if it used the STORED
method.
- ZipArchiveEntry#getLastModifiedDate uses
ZipEntry#getTime under the covers which may
return different times for the same archive when using
different versions of Java.
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