This is a collection of utilities to help improve the startup time of JRuby-based applications.
gem install jruby-startup
The utilities provided by this gem are described below.
The generate-appcds command is used to generate an AppCDS, or
"Application-specific Class Data Store" archive on OpenJDK 11 or
higher. This archive pre-processes the classes in JRuby to eliminate
some overhead at startup.
By using this utility and setting some environment variables, many JRuby commands can be sped up a fair amount.
Running generate-appcds alone will generate the AppCDS archive based
on a command line of -e 1 as passed to JRuby. You can provide a
different command line, in quotes, to the generate-appcds command.
$ generate-appcds
*** Outputting list of classes at /Users/headius/projects/jruby/lib/jruby.list
...
When the command has completed, you will see some environment variables to set that will enable the use of the AppCDS archive.
Bug reports and pull requests are welcome on GitHub at https://github.com/jruby/jruby-startup.