1. JRuby It's What's For Dinner
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2. Agenda Another year of JRuby The JVM: pragmatically awesome
1.9 support
King Pong
Best deployment evar
FFI = compatible C library access
All that other Java stuff
Getting going, getting involved

3. The JRuby Guys Tom Enebo and Charles Oliver Nutter
4-6 years as JRuby devs
2 years as JRuby devs at Sun Microsystems
12+ years as Java devs
Working from home (Minneapolis area)
Conference junkies

4. Another Year of JRuby Compiler finished Fall 2007
JRuby 1.1 RC cycle Winter 2008
1.1.5 is current release (this week!)
113 bugs fixed in 1.1.5, 1552 since last year
411 revisions in 1.1.5, 3141 since last year
Compatibility with is “done”
Performance is great, always improving
1.9 support, better Java interop on the way

5. The JVM: Pragmatically Awesome
OpenJDK (Hotspot)
Estimated 500 man-years
Legendary performance, GC (“faster than C++”)
Native JIT, profiled code inlining
Extremely stable, secure
A dynamic VM under the covers
Pervasive: you all probably have it
Why fight it? Why build new?

6. JRuby and the JVM AST (interpreter) App code Java calls JRuby Runtime
Parser
Ruby stdlib
Compiler
Core classes
(String, etc)
Precompiled
code
.class loading
Bytecode
Java calls

7. Ruby 1.9 Support Some libraries done, some coming soon
Parser support “real soon now”
M17N bits coming along
Bytecode engine prototype (not needed?)
1.8.6 and support in same binary
Hasn't taken very long; done by Christmas
DEMO

8. Use it if you choose it Java libraries can be trivially accessed
A million Java libraries to choose from
Ability to integrate with legacy “Java”
Cross-platform solution

9. Demo: King Pong JMonkeyEngine: 3D Scenegraph library
OpenGL, Used Commercially

10. Best Deployment Evar! New GlassFish gem release 0.9.0
3.9MB production web app server
Single-process deployment, across cores
Any web framework
Simplest deployment possible:
gem install glassfish
glassfish <app dir>
There is no step three
DEMO

11. The Holy Grail JRuby uses real native threads
Rails 2.2 “thread safety” is a big deal
One JRuby instance
Reduced warm-up time
Reduced memory

12. The “Lame” Test Simple 1 controller, 1 model, 1 view app
Send 1000 reqs with concurrency 10 (ab)
GlassFish v2

13. FFI Foreign Function Interface Call C functions directly from Ruby
Portable, unlike extensions
Most extensions just wrap a library
Started in Rubinius
JRuby added support in 1.1.4
JRuby team: Ruby FFI gem
gem install ffi
This man did not use FFI. He wrote a C extension instead.

14. require 'ffi'
module POSIX
extend FFI::Library
# not usually necessary since libc is always linked
ffi_lib 'c'
attach_function :getuid, :getuid, [], :uint
attach_function :getpid, :getpid, [], :uint
end
puts "Process #{POSIX.getpid}, user #{POSIX.getuid}"

15. Java what? Servlets Use Rack + Warbler EE components (EJB, JMS ...)
GlassFish built-in Ruby support
Mobile, embedded
Definitely possible; nobody working on it
“Normal” Java type definition
Planned; lack of class declarations complicates

16. Users Speak Customers already have Java App Servers
Java libraries fill a void in Ruby (Swing)
Cross Platform (especially Windows)
Code obfuscation (AOT)
Odd platform (AS400)
Speed

17. Get Involved! www.jruby.org wiki.jruby.org #jruby on FreeNode IRC
headius (Twitter)
tom_enebo (Twitter)