无法识别的选项：--print-module-descriptor

Question

我正在按照 Java 9 Jigsaw 抢先体验版快速入门指南中的步骤操作 http://openjdk.java.net/projects/jigsaw/quick-start

➜  tmp java --version
java 9-ea
Java(TM) SE Runtime Environment (build 9-ea+172)
Java HotSpot(TM) 64-Bit Server VM (build 9-ea+172, mixed mode)

jar 命令是从正确的 Java9 目录中提取的。

➜  tmp which jar
/Library/Java/JavaVirtualMachines/jdk-9.jdk/Contents/Home/bin/jar

快速入门指南中的一个步骤说运行带有 --print-module-descriptor 选项的 jar 命令，但是当我尝试这样做时，我收到以下错误消息。

➜  tmp jar --print-module-descriptor --file=mlib/org.astro@1.0.jar
unrecognized option : --print-module-descriptor
Try `jar --help' for more information.

这个选项似乎在最新的抢先体验版本中不存在，是被删除了还是移到了其他地方？ jar --help 输出如下供参考

➜  tmp jar --help
Usage: jar [OPTION...] [ [--release VERSION] [-C dir] files] ...
jar creates an archive for classes and resources, and can manipulate or
restore individual classes or resources from an archive.

 Examples:
 # Create an archive called classes.jar with two class files:
 jar --create --file classes.jar Foo.class Bar.class
 # Create an archive using an existing manifest, with all the files in foo/:
 jar --create --file classes.jar --manifest mymanifest -C foo/ .
 # Create a modular jar archive, where the module descriptor is located in
 # classes/module-info.class:
 jar --create --file foo.jar --main-class com.foo.Main --module-version 1.0
     -C foo/ classes resources
 # Update an existing non-modular jar to a modular jar:
 jar --update --file foo.jar --main-class com.foo.Main --module-version 1.0
     -C foo/ module-info.class
 # Create a multi-release jar, placing some files in the META-INF/versions/9 directory:
 jar --create --file mr.jar -C foo classes --release 9 -C foo9 classes

To shorten or simplify the jar command, you can specify arguments in a separate
text file and pass it to the jar command with the at sign (@) as a prefix.

 Examples:
 # Read additional options and list of class files from the file classes.list
 jar --create --file my.jar @classes.list


 Main operation mode:

  -c, --create               Create the archive
  -i, --generate-index=FILE  Generate index information for the specified jar
                             archives
  -t, --list                 List the table of contents for the archive
  -u, --update               Update an existing jar archive
  -x, --extract              Extract named (or all) files from the archive
  -d, --describe-module      Print the module descriptor, or automatic module name

 Operation modifiers valid in any mode:

  -C DIR                     Change to the specified directory and include the
                             following file
  -f, --file=FILE            The archive file name. When omitted, either stdin or
                             stdout is used based on the operation
      --release VERSION      Places all following files in a versioned directory
                             of the jar (i.e. META-INF/versions/VERSION/)
  -v, --verbose              Generate verbose output on standard output

 Operation modifiers valid only in create and update mode:

  -e, --main-class=CLASSNAME The application entry point for stand-alone
                             applications bundled into a modular, or executable,
                             jar archive
  -m, --manifest=FILE        Include the manifest information from the given
                             manifest file
  -M, --no-manifest          Do not create a manifest file for the entries
      --module-version=VERSION    The module version, when creating a modular
                             jar, or updating a non-modular jar
      --hash-modules=PATTERN Compute and record the hashes of modules 
                             matched by the given pattern and that depend upon
                             directly or indirectly on a modular jar being
                             created or a non-modular jar being updated
  -p, --module-path          Location of module dependence for generating
                             the hash

 Operation modifiers valid only in create, update, and generate-index mode:

  -0, --no-compress          Store only; use no ZIP compression

 Other options:

  -h, --help[:compat]        Give this, or optionally the compatibility, help
      --help-extra           Give help on extra options
      --version              Print program version

 An archive is a modular jar if a module descriptor, 'module-info.class', is
 located in the root of the given directories, or the root of the jar archive
 itself. The following operations are only valid when creating a modular jar,
 or updating an existing non-modular jar: '--module-version',
 '--hash-modules', and '--module-path'.

 Mandatory or optional arguments to long options are also mandatory or optional
 for any corresponding short options.

Answer 1

是的，该选项似乎已替换为 --describe-module（显示在您发布的帮助输出中）。这是在 JDK-8176772 中完成的，在构建 162 中已解决。

无法识别的选项：--print-module-descriptor

unrecognized option : --print-module-descriptor

java

jar

java-9

java-platform-module-system