Versions Formats - JDK 5 Documentation v6.0, Java 2 SDK 英文文档
Appendix 2: Sun-Supported Specification-Version and Implementation-Version
Formats
Specification-Version and Implementation-Version
follow these rules for Sun products, and third-party products must follow the
same rules for Java Plug-in to make reliable decisions about whether an extension
is up-to-date or not:
The Specification-Version string will be of the form:
n1.n2[.n3]
where n1, n2, and n3 are integers, n1.n2
is the major version number, and optional n3 is the minor
version number (also referred to as the maintenance version number).
The Implementation-Version will be of the same form initially
but may:
- append with a preceding underscore("
_")n4n5to indicate a patch version number (also referred to as the update version number) - or append with a hyphen ("
-") a milestone name (ea,alpha,beta,rc...), which may also include a trailing integer number (ea1,beta2,rc1...).
Both patch version number and milestone name may not be used together in the
Implemenation-Version string.
The general form is as follows:
n1.n2[.n3][_<patch_number>|-<milestone_name>]
Integers (n1,n2, n3 ...), letters, dots,
hyphens, and underscores , may be used in the version format as described above;
no other characters ("*", "+"
...) are allowed.
Note that the Specification-Version and Implementation-Version
numbers are in theory independent, though in practice they are often in sync
with each other.
Examples:
Specification-Version examples: 1.3, 1.4
Implementation-Version examples: 1.3.1, 1.4.0_02,
1.4.0-beta3
While these are the rules, it is always a good idea when using a third-party
extension JAR to examine its MANIFEST.MF file to see
what actual values are in it. If it does not follow these rules, you may need
to change your applet JAR MANIFEST.MF accordingly
or alter the extension JAR.