> Currently, running `java` without any parameters will lead to an output that > is a full `--help`, which is over 100 lines (on my computer at least), and it > feels overwhelming. And many people might actually want to run JShell/REPL, > not the `java` executable, but it is difficult find out about JShell. > > The proposal herein is to print a much shorter help, together with a pointer > to JShell, when the executable does not know what to do. I.e. there is > nothing specified to start, and no option like `--help` is specified. In > particular, on my machine, it prints: > > Usage: java [java options...] <application> [application arguments...] > > Where <application> is one of: > <mainclass> to execute the main method of a compiled main > class > -jar <jarfile>.jar to execute the main class of a JAR archive > -m <module>[/<mainclass>] to execute the main class of a module > <sourcefile>.java to compile and execute a source-file program > > Where key java options include: > --class-path <class path> > where <class path> is a list of directories and JAR archives to search > for class files, separated by ":" > --module-path <module path> > where <module path> is a list of directories and JAR archives to search > for modules, separated by ":" > -version > to print product version to the error stream and exit > > For additional help on usage: java --help > For an interactive Java environment: jshell > > > The full `java -help` with these changes is as follows: > > Usage: java [options] <mainclass> [args...] > (to execute a class) > or java [options] -jar <jarfile>.jar [args...] > (to execute a jar file) > or java [options] -m <module>[/<mainclass>] [args...] > java [options] --module <module>[/<mainclass>] [args...] > (to execute the main class in a module) > or java [options] <sourcefile>.java [args] > (to execute a source-file program) > > Arguments following the main class, source file, -jar <jarfile>.jar, > -m or --module <module>/<mainclass> are passed as the arguments to > main class. > > where options include: > > -cp <class search path of directories and zip/jar files> > -classpath <class search path of directories and zip/jar files> > --class-path <class search path of directories and zip/jar files> > A ":"-separated list of directories, JAR archives, > and ZIP archives to search for class files. > -p <module path> > --module-path <module path>... > ...
Jan Lahoda has updated the pull request incrementally with two additional commits since the last revision: - Dropping printing of the version. - Dropping the version from the concise help ------------- Changes: - all: https://git.openjdk.org/jdk/pull/21411/files - new: https://git.openjdk.org/jdk/pull/21411/files/439fa40f..0d4eed05 Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=21411&range=09 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=21411&range=08-09 Stats: 23 lines in 5 files changed: 2 ins; 20 del; 1 mod Patch: https://git.openjdk.org/jdk/pull/21411.diff Fetch: git fetch https://git.openjdk.org/jdk.git pull/21411/head:pull/21411 PR: https://git.openjdk.org/jdk/pull/21411
