RFR: JDK-8183579: refactor and cleanup launcher help messages

Mandy Chung mandy.chung at oracle.com
Wed Jul 26 15:59:43 UTC 2017

> On Jul 20, 2017, at 11:53 AM, Kumar Srinivasan <kumar.x.srinivasan at oracle.com> wrote:
> Hi,
> Please review refactoring and clean up of the java launcher's help/usage
> messages.
> The highlights of the changes are as follows:
> 1. Helper.java: is renamed from LauncherHelper.java, simpler name,
>    containing mostly methods to help with class loading, module assistance etc.

There are tests depending on `sun.launcher.LauncherHelper` class name.
I actually like LauncherHelper better than Helper to make it clear
what it is just by its simple name.

> Webrev:
> http://cr.openjdk.java.net/~ksrini/8183579/webrev.00/

  40 # Translators please note do not translate the options themselves

Option names are no longer in the resource bundle.
It would be helpful to add the comment describing the key name

A newline between each option may help readability.
Since the whitespace in description is irrelevant, maybe keep the indentation
to 4 space?

Does the help message show the options in the order listed here?
I would hope it uses the order of the Option enums.  If so, we could
list them in alphabetical order in launcher.properties.

  80 java.launcher.opt.x.desc = print help on extra options to the error stream

Should $OPTION_NAME match the option name (rather than toLowerCase)?

 311         Arrays.asList(Option.values()).stream()

Alternative: Stream(Option.values())

This class includes the entry point for -XshowSettings but not other options such as —-list-modules.  It may cause confusion to which class a new launcher option is added.  It may be okay.   Maybe just move the code for printing the help messages in Option class and consider the refactoring for -XshowSetting and other options in the future. 


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