Summary

Document the ZIP FS properties "compressionMethod" and "releaseVersion".

Problem

The ZIP File System supports several undocumented properties such as "noCompression" and "multi-release".

At this time, we will document and support the properties "compressionMethod"(formerly "noCompression") and "releaseVersion" (formerly "multi-release").

Solution

Document the "compressionMethod"(formerly "noCompression") and "releaseVersion" (formerly "multi-release") properties while still supporting "noCompression" and "multi-release" for backwards compatibility.

We will consider supporting and documenting the remaining un-documented properties once there is adequate testing and a belief that supporting the properties brings value to the developer community.

Specification

The following properties are added (please refer to the attached diff module-info.java.diff-Sept_23_2019.txt):

compressionMethod - "DEFLATED"(default) - The value representing the compression method to use when writing entries to the Zip file system.

• If the value is "STORED", the Zip file system provider will not compress entries when writing to the Zip file system.
• If the value is "DEFLATED" or the property is not set, the Zip file system provider will use data compression when writing entries to the Zip file system.
• If the value is not "STORED" or "DEFLATED", an IllegalArgumentException will be thrown when creating the Zip filesystem.

releaseVersion - null/not set(default) - A value representing the version entry to use when accessing a multi-release JAR. If the JAR is not a multi-release JAR, the value will be ignored and the JAR will considered un-versioned.

The value must be either the string "runtime" or represent a valid Java SE Platform version number, such as 9 or 14, in order to determine the version entry.

• If the value is null or the property is not set, then the JAR will be treated as an un-versioned JAR.
• If the value is "runtime" , the version entry will be determined by invoking Runtime.Version.feature().
• If the value does not represent a valid Java SE Platform version number, an IllegalArgumentException will be thrown.