java.util.zip (Java SE 26 & JDK 26)
Description: declaration: module: java.base, package: java.util.zip
Keywords: java.util.zip package

# Package java.util.zip

package java.util.zip
Provides classes for reading and writing the standard ZIP and GZIP file formats. Also includes classes for compressing and decompressing data using the DEFLATE compression algorithm, which is used by the ZIP and GZIP file formats. Additionally, there are utility classes for computing the CRC-32, CRC-32C and Adler-32 checksums of arbitrary input streams.

## Package Specification

- Info-ZIP Application Note 970311 - a detailed description of the Info-ZIP format upon which the `java.util.zip` classes are based.
- An implementation may optionally support the ZIP64(tm) format extensions defined by the PKWARE ZIP File Format Specification. The ZIP64(tm) format extensions are used to overcome the size limitations of the original ZIP format.
- APPENDIX D of PKWARE ZIP File Format Specification - Language Encoding Flag to encode ZIP entry filename and comment fields using UTF-8.
- ZLIB Compressed Data Format Specification version 3.3 (pdf) (RFC 1950)
- DEFLATE Compressed Data Format Specification version 1.3 (pdf) (RFC 1951)
- GZIP file format specification version 4.3 (pdf) (RFC 1952)
- CRC-32 checksum is described in RFC 1952 (above)
- CRC-32C checksum is described in Internet Small Computer Systems Interface (iSCSI) (pdf) (RFC 3720)
- Adler-32 checksum is described in RFC 1950 (above)

Since:
  1.1
External Specifications
  - RFC 1950: ZLIB Compressed Data Format Specification version 3.3
  - RFC 1951: DEFLATE Compressed Data Format Specification version 1.3
  - RFC 1952: GZIP file format specification version 4.3
  - RFC 3720: Internet Small Computer Systems Interface (iSCSI)

- Related Packages
  Package
  Description
  java.util
  Contains the collections framework, some internationalization support classes, a service loader, properties, random number generation, string parsing and scanning classes, base64 encoding and decoding, a bit array, and several miscellaneous utility classes.
- Class
  Description
  Adler32
  A class that can be used to compute the Adler-32 checksum of a data stream.
  CheckedInputStream
  An input stream that also maintains a checksum of the data being read.
  CheckedOutputStream
  An output stream that also maintains a checksum of the data being written.
  Checksum
  An interface representing a data checksum.
  CRC32
  A class that can be used to compute the CRC-32 of a data stream.
  CRC32C
  A class that can be used to compute the CRC-32C of a data stream.
  DataFormatException
  Signals that a data format error has occurred.
  Deflater
  This class provides support for general purpose compression using the popular ZLIB compression library.
  DeflaterInputStream
  Implements an input stream filter for compressing data in the "deflate" compression format.
  DeflaterOutputStream
  This class implements an output stream filter for compressing data in the "deflate" compression format.
  GZIPInputStream
  This class implements a stream filter for reading compressed data in the GZIP file format.
  GZIPOutputStream
  This class implements a stream filter for writing compressed data in the GZIP file format.
  Inflater
  This class provides support for general purpose decompression using the popular ZLIB compression library.
  InflaterInputStream
  This class implements a stream filter for uncompressing data in the "deflate" compression format.
  InflaterOutputStream
  Implements an output stream filter for uncompressing data stored in the "deflate" compression format.
  ZipEntry
  This class is used to represent a ZIP file entry.
  ZipError
  Deprecated, for removal: This API element is subject to removal in a future version.
  ZipError is no longer used and is obsolete.
  ZipException
  Signals that a ZIP exception of some sort has occurred.
  ZipFile
  This class is used to read entries from a ZIP file.
  ZipInputStream
  An input stream for reading compressed and uncompressed ZIP file entries from a stream of bytes in the ZIP file format.
  ZipOutputStream
  This class implements an output stream filter for writing files in the ZIP file format.