Key Features

Appending To Existing ZIP Files

New ZIP entries can get appended to existing ZIP files.

To use this feature with the ZIP API, call ZipOutputStream(OutputStream, ZipFile).

Recovery Of Lost ZIP Entries

When reading truncated ZIP files, lost entries can get recovered.

To use this feature with the ZIP API, call ZipFile.recoverLostEntries().

WinZip AES Specification

When reading or writing a ZIP file, ZIP entry data can get encrypted and authenticated according to the WinZip AES specification.

To use this feature with the ZIP API, call ZipEntry.setEncrypted(boolean) first. Then call ZipFile.setCryptoParameters(ZipCryptoParameters) or ZipOutputStream.setCryptoParameters(ZipCryptoParameters) respectively.

Note that the WinZip AES encryption scheme does not encrypt and not authenticate any ZIP entry meta data, i.e. neither the ZIP entry comments, the ZIP entry names nor the central directory. If you want this, then please consider using the ZIP.RAES file format instead.

BZIP2 Compression

When reading or writing a ZIP file, ZIP entry data can get decompressed or compressed using the BZIP2 algorithm. To use this feature when reading a BZIP compressed ZIP entry, you don't need to do anything - decompression happens automatically.

To use this feature for writing a BZIP2 compressed ZIP entry with the ZIP API, call ZipEntry.setMethod(int)

Selectable Character Sets

The character set for reading and writing ZIP comments and ZIP entry names can get set when using a file system driver or the ZIP classes directly.

To use this feature with the ZIP API, call ZipOutputStream(OutputStream, Charset) or ZipFile(File, Charset).

External File Attributes

External file attributes can get used to set executable bits for third party tools, etc.

To use this feature with the ZIP API, call ZipEntry.setExternalAttributes(long).

ZIP64 Extensions

ZIP64 extensions are automatically and transparently read and written when accessing ZIP files of more than 4 GB size.