Starting from 7u79, the usage string of jar utility mentions the option '-n', though it is not supported in Java 7.
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C:\Program Files\Java\jdk1.7.0_79\bin>jar
Usage: jar {ctxui}[vfmn0PMe] [jar-file] [manifest-file] [entry-point] [-C dir] files ...
Options:
    -c create new archive
    -t list table of contents for archive
    -x extract named (or all) files from archive
    -u update existing archive
    -v generate verbose output on standard output
    -f specify archive file name
    -m include manifest information from specified manifest file
    -e specify application entry point for stand-alone application
        bundled into an executable jar file
    -0 store only; use no ZIP compression
    -P preserve leading '/' (absolute path) and ".." (parent directory) components from file names
    -M do not create a manifest file for the entries
    -i generate index information for the specified jar files
    -C change to the specified directory and include the following file
If any file is a directory then it is processed recursively.
...
C:\Program Files\Java\jdk1.7.0_79\bin>jar -n
Illegal option: n
Usage: jar {ctxui}[vfmn0PMe] [jar-file] [manifest-file] [entry-point] [-C dir] files ...
Options:
    -c create new archive
    -t list table of contents for archive
    -x extract named (or all) files from archive
...
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It looks like a copy-paste error during backporting from Java 8/9.
Not reproducible with 7u76.