<s>
JRuby	B-Language
is	O
an	O
implementation	O
of	O
the	O
Ruby	B-Language
programming	I-Language
language	I-Language
atop	O
the	O
Java	B-Language
Virtual	I-Language
Machine	I-Language
,	O
written	O
largely	O
in	O
Java	B-Device
.	O
</s>
<s>
It	O
is	O
free	B-Application
software	I-Application
released	O
under	O
a	O
three-way	O
EPL/GPL/LGPL	O
license	O
.	O
</s>
<s>
JRuby	B-Language
is	O
tightly	O
integrated	O
with	O
Java	B-Device
to	O
allow	O
the	O
embedding	O
of	O
the	O
interpreter	B-Application
into	O
any	O
Java	B-Device
application	O
with	O
full	O
two-way	O
access	O
between	O
the	O
Java	B-Device
and	O
the	O
Ruby	B-Language
code	O
(	O
similar	O
to	O
Jython	B-Language
for	O
the	O
Python	O
language	O
)	O
.	O
</s>
<s>
JRuby	B-Language
's	O
lead	O
developers	O
are	O
Charles	O
Oliver	O
Nutter	O
and	O
Thomas	O
Enebo	O
,	O
with	O
many	O
current	O
and	O
past	O
contributors	O
including	O
Ola	O
Bini	O
and	O
Nick	O
Sieger	O
.	O
</s>
<s>
In	O
September	O
2006	O
,	O
Sun	O
Microsystems	O
hired	O
Enebo	O
and	O
Nutter	O
to	O
work	O
on	O
JRuby	B-Language
full-time	O
.	O
</s>
<s>
In	O
June	O
2007	O
,	O
ThoughtWorks	B-Application
hired	O
Ola	O
Bini	O
to	O
work	O
on	O
Ruby	B-Language
and	O
JRuby	B-Language
.	O
</s>
<s>
In	O
July	O
2009	O
,	O
the	O
JRuby	B-Language
developers	O
left	O
Sun	O
to	O
continue	O
JRuby	B-Language
development	O
at	O
Engine	O
Yard	O
.	O
</s>
<s>
In	O
May	O
2012	O
,	O
Nutter	O
and	O
Enebo	O
left	O
Engine	O
Yard	O
to	O
work	O
on	O
JRuby	B-Language
at	O
Red	O
Hat	O
.	O
</s>
<s>
JRuby	B-Language
was	O
originally	O
created	O
by	O
Jan	O
Arne	O
Petersen	O
,	O
in	O
2001	O
.	O
</s>
<s>
At	O
that	O
time	O
and	O
for	O
several	O
years	O
following	O
,	O
the	O
code	O
was	O
a	O
direct	O
port	O
of	O
the	O
Ruby	B-Language
1.6	O
C	B-Language
code	O
.	O
</s>
<s>
With	O
the	O
release	O
of	O
Ruby	B-Language
1.8.6	O
,	O
an	O
effort	O
began	O
to	O
update	O
JRuby	B-Language
to	O
1.8.6	O
features	O
and	O
semantics	O
.	O
</s>
<s>
JRuby	B-Language
1.1	O
added	O
Just-in-time	O
compilation	O
and	O
Ahead-of-time	B-Application
compilation	I-Application
modes	O
to	O
JRuby	B-Language
and	O
was	O
already	O
faster	O
in	O
most	O
cases	O
than	O
the	O
then-current	O
Ruby	B-Language
1.8.7	O
reference	O
implementation	O
.	O
</s>
<s>
JRuby	B-Language
packages	O
are	O
available	O
for	O
most	O
platforms	O
;	O
Fedora	O
9	O
was	O
among	O
the	O
first	O
to	O
include	O
it	O
as	O
a	O
standard	O
package	O
at	O
JRuby	B-Language
1.1.1	O
.	O
</s>
<s>
In	O
July	O
2009	O
,	O
the	O
core	O
JRuby	B-Language
developers	O
at	O
Sun	O
Microsystems	O
,	O
Charles	O
Oliver	O
Nutter	O
,	O
Thomas	O
Enebo	O
and	O
Nick	O
Sieger	O
,	O
joined	O
Engine	O
Yard	O
to	O
continue	O
JRuby	B-Language
development	O
.	O
</s>
<s>
In	O
May	O
2012	O
,	O
Nutter	O
and	O
Enebo	O
left	O
Engine	O
Yard	O
to	O
work	O
on	O
JRuby	B-Language
at	O
Red	O
Hat	O
.	O
</s>
<s>
JRuby	B-Language
has	O
supported	O
compatibility	O
with	O
Ruby	B-Language
MRI	I-Language
versions	O
1.6	O
through	O
1.9.3	O
.	O
</s>
<s>
JRuby	B-Language
1.0	O
supported	O
Ruby	B-Language
1.8.6	O
,	O
with	O
JRuby	B-Language
1.4.0	O
updating	O
that	O
compatibility	O
to	O
Ruby	B-Language
1.8.7	O
.	O
</s>
<s>
JRuby	B-Language
1.6.0	O
added	O
simultaneous	O
support	O
for	O
Ruby	B-Language
1.9.2	O
,	O
with	O
JRuby	B-Language
1.7.0	O
making	O
Ruby	B-Language
1.9.3	O
the	O
default	O
execution	O
mode	O
(	O
Ruby	B-Language
1.8.7	O
compatibility	O
is	O
available	O
via	O
a	O
command-line	O
flag	O
)	O
.	O
</s>
<s>
JRuby	B-Language
9.0.0.0	O
added	O
support	O
for	O
Ruby	B-Language
2.2	O
.	O
</s>
<s>
The	O
current	O
version	O
of	O
JRuby	B-Language
(	O
9.4.1.0	O
)	O
targets	O
Ruby	B-Language
3.1	O
,	O
though	O
some	O
3.1	O
features	O
are	O
still	O
in	O
work	O
.	O
</s>
<s>
JRuby	B-Language
has	O
been	O
able	O
to	O
run	O
the	O
Ruby	B-Application
on	I-Application
Rails	I-Application
web	O
framework	O
since	O
version	O
0.9	O
(	O
May	O
2006	O
)	O
,	O
with	O
the	O
ability	O
to	O
execute	O
RubyGems	B-Application
and	O
WEBrick	B-Application
.	O
</s>
<s>
JRuby	B-Language
version	O
1.0	O
successfully	O
passed	O
nearly	O
all	O
of	O
Rails	O
's	O
own	O
test	O
cases	O
.	O
</s>
<s>
Since	O
then	O
,	O
developers	O
have	O
begun	O
to	O
use	O
JRuby	B-Language
for	O
Rails	O
applications	O
in	O
production	O
environments	O
.	O
</s>
<s>
On	O
February	O
27	O
,	O
2008	O
,	O
Sun	O
Microsystems	O
and	O
the	O
University	O
of	O
Tokyo	O
announced	O
a	O
joint-research	O
project	O
to	O
implement	O
a	O
virtual	O
machine	O
capable	O
of	O
executing	O
more	O
than	O
one	O
Ruby	B-Language
or	O
JRuby	B-Language
application	O
on	O
one	O
interpreter	B-Application
.	O
</s>
<s>
JSR	B-Application
292	I-Application
(	O
Supporting	O
Dynamically	O
Typed	O
Languages	O
on	O
the	O
JavaTM	O
Platform	O
)	O
proposes	O
:	O
</s>
<s>
adding	O
a	O
new	O
invokedynamic	B-Application
instruction	O
at	O
the	O
JVM	B-Language
level	O
,	O
allowing	O
method	O
invocation	O
using	O
dynamic	O
type	O
checking	O
,	O
</s>
<s>
The	O
Sun	O
Open	O
source	O
project	O
Multi	B-Application
Language	I-Application
Virtual	I-Application
Machine	I-Application
aims	O
to	O
prototype	O
this	O
JSR	O
.	O
</s>
<s>
The	O
first	O
working	O
prototype	O
,	O
developed	O
as	O
a	O
patch	O
on	O
OpenJDK	B-Language
,	O
was	O
announced	O
and	O
made	O
available	O
on	O
end	O
of	O
August	O
2008	O
.	O
</s>
<s>
The	O
JRuby	B-Language
team	O
has	O
implemented	O
dynamic	O
invocation	O
into	O
their	O
codebase	O
.	O
</s>
<s>
Version	O
1.7.0	O
enabled	O
it	O
by	O
default	O
on	O
Java	B-Device
8	O
builds	O
.	O
</s>
<s>
This	O
table	O
presents	O
only	O
releases	O
that	O
present	O
significant	O
steps	O
in	O
JRuby	B-Language
history	O
,	O
aside	O
from	O
versions	O
that	O
mainly	O
fixed	O
bugs	O
and	O
improved	O
performance	O
.	O
</s>
<s>
Since	O
early	O
2006	O
,	O
the	O
current	O
JRuby	B-Language
core	O
team	O
has	O
endeavored	O
to	O
move	O
JRuby	B-Language
beyond	O
being	O
a	O
simple	O
C	B-Language
port	O
,	O
to	O
support	O
better	O
performance	O
and	O
to	O
aid	O
eventual	O
compilation	O
to	O
Java	B-Language
bytecode	I-Language
.	O
</s>
<s>
To	O
support	O
this	O
end	O
,	O
the	O
team	O
set	O
an	O
ambitious	O
goal	O
:	O
to	O
be	O
able	O
to	O
run	O
Ruby	B-Application
on	I-Application
Rails	I-Application
unmodified	O
using	O
JRuby	B-Language
.	O
</s>
<s>
In	O
the	O
process	O
of	O
achieving	O
this	O
goal	O
,	O
the	O
JRuby	B-Language
test	O
suite	O
expanded	O
to	O
such	O
extent	O
that	O
the	O
team	O
gained	O
confidence	O
in	O
the	O
"	O
correctness	O
"	O
of	O
JRuby	B-Language
.	O
</s>
<s>
As	O
a	O
result	O
,	O
toward	O
the	O
end	O
of	O
2006	O
and	O
in	O
the	O
beginning	O
of	O
2007	O
,	O
they	O
began	O
to	O
commit	O
much	O
more	O
complicated	O
redesigns	O
and	O
refactorings	O
of	O
JRuby	B-Language
's	O
core	O
subsystems	O
.	O
</s>
<s>
JRuby	B-Language
is	O
designed	O
to	O
work	O
as	O
a	O
mixed-mode	O
virtual	O
machine	O
for	O
Ruby	B-Language
,	O
where	O
code	O
can	O
be	O
either	O
interpreted	B-Application
directly	O
,	O
just-in-time	O
compiled	O
at	O
runtime	O
to	O
Java	B-Language
bytecode	I-Language
,	O
or	O
ahead-of-time	B-Application
compiled	O
to	O
Java	B-Language
bytecode	I-Language
before	O
execution	O
.	O
</s>
<s>
Until	O
October	O
2007	O
,	O
only	O
the	O
interpreted	B-Application
mode	O
supported	O
all	O
Ruby	B-Language
's	O
constructs	O
,	O
but	O
a	O
full	O
AOT/JIT	O
compiler	O
is	O
available	O
since	O
version	O
1.1	O
.	O
</s>
<s>
The	O
compiler	O
design	O
allows	O
for	O
interpreted	B-Application
and	O
compiled	O
code	O
to	O
run	O
side-by-side	O
,	O
as	O
well	O
as	O
decompilation	O
to	O
reoptimize	O
and	O
outputting	O
generated	O
bytecode	O
as	O
Java	B-Device
class	O
files	O
.	O
</s>
<s>
JRuby	B-Language
has	O
built-in	O
support	O
for	O
Rails	O
,	O
RSpec	B-Application
,	O
Rake	B-Application
,	O
and	O
RubyGems	B-Application
.	O
</s>
<s>
It	O
embeds	O
an	O
FFI	B-Application
subsystem	O
to	O
allow	O
the	O
use	O
of	O
C	B-Language
libraries	O
bundled	O
as	O
gems	B-Application
.	O
</s>
<s>
It	O
also	O
allows	O
launching	O
the	O
Interactive	O
Ruby	B-Language
Shell	O
(	O
irb	O
)	O
as	O
Ruby	B-Language
MRI	I-Language
does	O
.	O
</s>
<s>
The	O
Netbeans	O
Ruby	B-Language
Pack	O
,	O
available	O
in	O
NetBeans	O
6	O
,	O
allows	O
IDE	O
development	O
with	O
Ruby	B-Language
and	O
JRuby	B-Language
,	O
as	O
well	O
as	O
Ruby	B-Application
on	I-Application
Rails	I-Application
for	O
the	O
two	O
implementations	O
of	O
Ruby	B-Language
.	O
</s>
<s>
JRuby	B-Language
is	O
similar	O
to	O
the	O
standard	O
Ruby	B-Language
interpreter	B-Application
except	O
written	O
in	O
Java	B-Device
.	O
</s>
<s>
JRuby	B-Language
features	O
some	O
of	O
the	O
same	O
concepts	O
,	O
including	O
object-oriented	B-Language
programming	I-Language
,	O
and	O
dynamic	O
typing	O
as	O
Ruby	B-Language
.	O
</s>
<s>
The	O
key	O
difference	O
is	O
that	O
JRuby	B-Language
is	O
tightly	O
integrated	O
with	O
Java	B-Device
,	O
and	O
can	O
be	O
called	O
directly	O
from	O
Java	B-Device
programs	O
.	O
</s>
<s>
Java	B-Device
has	O
significant	O
footing	O
in	O
the	O
development	O
of	O
web	O
applications	O
.	O
</s>
<s>
One	O
powerful	O
feature	O
of	O
JRuby	B-Language
is	O
its	O
ability	O
to	O
invoke	O
the	O
classes	O
of	O
the	O
Java	B-Device
Platform	I-Device
.	O
</s>
<s>
To	O
do	O
this	O
,	O
one	O
must	O
first	O
load	O
JRuby	B-Language
's	O
Java	B-Device
support	O
,	O
by	O
calling	O
"	O
require	O
'	O
java	B-Device
 '	O
"	O
.	O
</s>
<s>
The	O
following	O
example	O
creates	O
a	O
Java	B-Device
JFrame	O
with	O
a	O
JLabel	O
:	O
</s>
<s>
JRuby	B-Language
also	O
allows	O
the	O
user	O
to	O
call	O
Java	B-Language
code	I-Language
using	O
the	O
more	O
Ruby-like	O
underscore	O
method	O
naming	O
and	O
to	O
refer	O
to	O
JavaBean	O
properties	O
as	O
attributes	O
:	O
</s>
<s>
JRuby	B-Language
can	O
just	O
as	O
easily	O
be	O
called	O
from	O
Java	B-Device
,	O
using	O
either	O
the	O
JSR	B-Language
223	I-Language
Scripting	B-Language
for	I-Language
Java	I-Language
6	O
or	O
the	O
Apache	B-Language
Bean	I-Language
Scripting	I-Language
framework	O
.	O
</s>
<s>
According	O
to	O
some	O
benchmarks	O
,	O
JRuby	B-Language
is	O
faster	O
than	O
alternatives	O
.	O
</s>
<s>
The	O
time	O
it	O
takes	O
for	O
a	O
Java	B-Language
Virtual	I-Language
Machine	I-Language
itself	O
to	O
load	O
is	O
often	O
excluded	O
from	O
execution	O
times	O
when	O
calculating	O
benchmarks	O
.	O
</s>
<s>
JRuby	B-Language
has	O
the	O
significant	O
architectural	O
advantage	O
to	O
be	O
able	O
to	O
leverage	O
JVM	B-Language
threads	O
without	O
being	O
constrained	O
by	O
a	O
global	B-Operating_System
interpreter	I-Operating_System
lock	I-Operating_System
(	O
similarly	O
to	O
Rubinius	B-Application
)	O
,	O
therefore	O
achieving	O
full	O
parallelism	O
within	O
a	O
process	O
,	O
which	O
Ruby	B-Language
MRI	I-Language
cannot	O
achieve	O
despite	O
leveraging	O
OS	O
threads	O
.	O
</s>
<s>
In	O
a	O
real	O
Mongrel	B-Application
web	I-Application
server	I-Application
application	O
tested	O
in	O
2007	O
,	O
JRuby	B-Language
performance	O
is	O
better	O
than	O
Ruby	B-Language
MRI	I-Language
1.8	O
,	O
after	O
the	O
Java	B-Language
Virtual	I-Language
Machine	I-Language
had	O
been	O
instantiated	O
.	O
</s>
<s>
In	O
a	O
2007	O
benchmark	O
of	O
Ruby	B-Language
implementations	O
,	O
JRuby	B-Language
was	O
faster	O
than	O
Ruby	B-Language
MRI	I-Language
1.8	O
in	O
some	O
tests	O
,	O
but	O
YARV	B-Language
outperformed	O
both	O
of	O
them	O
.	O
</s>
<s>
As	O
of	O
April	O
2014	O
,	O
in	O
The	O
Computer	O
Language	O
Benchmarks	O
Game	O
,	O
JRuby	B-Language
1.7.4	O
typically	O
has	O
the	O
same	O
performance	O
as	O
Ruby	B-Language
MRI	I-Language
2.1.0	O
,	O
but	O
uses	O
more	O
memory	O
.	O
</s>
