<s>
The	O
Java	B-Library
Class	I-Library
Library	I-Library
(	O
JCL	O
)	O
is	O
a	O
set	O
of	O
dynamically	O
loadable	O
libraries	O
that	O
Java	B-Language
Virtual	I-Language
Machine	I-Language
(	O
JVM	B-Language
)	O
languages	O
can	O
call	O
at	O
run	B-Library
time	I-Library
.	O
</s>
<s>
Because	O
the	O
Java	B-Device
Platform	I-Device
is	O
not	O
dependent	O
on	O
a	O
specific	O
operating	B-General_Concept
system	I-General_Concept
,	O
applications	O
cannot	O
rely	O
on	O
any	O
of	O
the	O
platform-native	O
libraries	O
.	O
</s>
<s>
Instead	O
,	O
the	O
Java	B-Device
Platform	I-Device
provides	O
a	O
comprehensive	O
set	O
of	O
standard	B-Library
class	I-Library
libraries	I-Library
,	O
containing	O
the	O
functions	O
common	O
to	O
modern	O
operating	B-General_Concept
systems	I-General_Concept
.	O
</s>
<s>
JCL	O
serves	O
three	O
purposes	O
within	O
the	O
JVM	B-Language
:	O
</s>
<s>
Like	O
other	O
standard	B-Library
code	I-Library
libraries	I-Library
,	O
they	O
provide	O
the	O
programmer	O
a	O
well-known	O
set	O
of	O
useful	O
facilities	O
,	O
such	O
as	O
container	B-Application
classes	I-Application
and	O
regular	B-Language
expression	I-Language
processing	O
.	O
</s>
<s>
The	O
library	O
provides	O
an	O
abstract	O
interface	O
to	O
tasks	O
that	O
would	O
normally	O
depend	O
heavily	O
on	O
the	O
hardware	B-Architecture
and	O
operating	B-General_Concept
system	I-General_Concept
,	O
such	O
as	O
network	B-Architecture
access	O
and	O
file	B-Application
access	I-Application
.	O
</s>
<s>
Some	O
underlying	O
platforms	O
may	O
not	O
support	O
all	O
of	O
the	O
features	O
a	O
Java	B-Device
application	O
expects	O
.	O
</s>
<s>
JCL	O
is	O
almost	O
entirely	O
written	O
in	O
Java	B-Device
,	O
except	O
for	O
the	O
parts	O
that	O
need	O
direct	O
access	O
to	O
the	O
hardware	B-Architecture
and	O
operating	B-General_Concept
system	I-General_Concept
(	O
such	O
as	O
for	O
I/O	B-General_Concept
or	O
bitmap	O
graphics	O
)	O
.	O
</s>
<s>
The	O
classes	O
that	O
give	O
access	O
to	O
these	O
functions	O
commonly	O
use	O
Java	B-Language
Native	I-Language
Interface	I-Language
wrappers	O
to	O
access	O
operating	B-General_Concept
system	I-General_Concept
APIs	B-General_Concept
.	O
</s>
<s>
Almost	O
all	O
of	O
JCL	O
is	O
stored	O
in	O
a	O
single	O
Java	B-Language
archive	I-Language
file	B-Operating_System
called	O
"	O
rt.jar	O
"	O
which	O
is	O
provided	O
with	O
JRE	O
and	O
JDK	B-Language
distributions	O
.	O
</s>
<s>
The	O
Java	B-Library
Class	I-Library
Library	I-Library
(	O
rt.jar	O
)	O
is	O
located	O
in	O
the	O
default	O
bootstrap	O
classpath	B-Language
and	O
does	O
not	O
have	O
to	O
appear	O
in	O
the	O
classpath	B-Language
declared	O
for	O
the	O
application	O
.	O
</s>
<s>
The	O
runtime	B-Library
uses	O
the	O
bootstrap	O
class	O
loader	O
to	O
find	O
the	O
JCL	O
.	O
</s>
<s>
The	O
Java	B-Language
Module	I-Language
System	I-Language
(	O
part	O
of	O
the	O
Java	B-Device
9	O
release	O
)	O
broke	O
the	O
monolithic	O
"	O
rt.jar	O
"	O
JAR	B-Language
file	I-Language
and	O
modularized	O
the	O
JCL	O
itself	O
in	O
several	O
modules	O
with	O
specified	O
dependencies	O
.	O
</s>
<s>
Any	O
Java	B-Language
implementation	I-Language
must	O
pass	O
the	O
Java	B-Device
Technology	I-Device
Compatibility	O
Kit	O
tests	O
for	O
compliance	O
,	O
which	O
includes	O
JCL	O
tests	O
.	O
</s>
<s>
JCL	O
Features	O
are	O
accessed	O
through	O
classes	O
provided	O
in	O
packages	B-Language
.	O
</s>
<s>
contains	O
fundamental	O
classes	O
and	O
interfaces	B-Language
closely	O
tied	O
to	O
the	O
language	O
and	O
runtime	B-Library
system	O
.	O
</s>
<s>
I/O	B-General_Concept
and	O
networking	B-Architecture
access	O
the	O
platform	O
file	B-Application
system	I-Application
,	O
and	O
more	O
generally	O
networks	B-Architecture
through	O
the	O
,	O
and	O
packages	B-Language
.	O
</s>
<s>
For	O
networking	B-Architecture
,	O
SCTP	B-Protocol
is	O
available	O
through	O
.	O
</s>
<s>
Collections	B-Application
and	O
Utilities	O
:	O
built-in	O
Collection	O
data	B-General_Concept
structures	I-General_Concept
,	O
and	O
utility	O
classes	O
,	O
for	O
Regular	B-Language
expressions	I-Language
,	O
Concurrency	B-Architecture
,	O
logging	B-Application
and	O
Data	B-General_Concept
compression	I-General_Concept
.	O
</s>
<s>
GUI	B-Application
and	O
2D	O
Graphics	O
:	O
the	O
AWT	B-Language
package	O
(	O
)	O
basic	O
GUI	B-Application
operations	O
and	O
binds	O
to	O
the	O
underlying	O
native	O
system	O
.	O
</s>
<s>
It	O
also	O
contains	O
the	O
2D	O
Graphics	O
API	B-General_Concept
.	O
</s>
<s>
The	O
Swing	B-Language
package	O
(	O
)	O
is	O
built	O
on	O
AWT	B-Language
and	O
provides	O
a	O
platform-independent	O
widget	B-Library
toolkit	I-Library
,	O
as	O
well	O
as	O
a	O
Pluggable	B-Language
look	I-Language
and	I-Language
feel	I-Language
.	O
</s>
<s>
Sound	O
:	O
interfaces	B-Language
and	O
classes	O
for	O
reading	O
,	O
writing	O
,	O
sequencing	O
,	O
and	O
synthesizing	O
of	O
sound	O
data	O
.	O
</s>
<s>
Image	O
package	O
:	O
and	O
provide	O
APIs	B-General_Concept
to	O
write	O
,	O
read	O
,	O
and	O
modify	O
images	O
.	O
</s>
<s>
XML	B-Protocol
:	O
SAX	B-Application
,	O
DOM	B-General_Concept
,	O
StAX	B-Language
,	O
XSLT	B-Application
transforms	I-Application
,	O
XPath	B-Language
and	O
various	O
APIs	B-General_Concept
for	O
Web	O
services	O
,	O
as	O
SOAP	B-Application
protocol	I-Application
and	O
JAX-WS	B-Language
.	O
</s>
<s>
Access	O
to	O
Scripting	B-Language
engines	I-Language
:	O
The	O
package	O
gives	O
access	O
to	O
any	O
conforming	O
Scripting	B-Language
language	I-Language
.	O
</s>
<s>
Java	B-Device
Beans	O
:	O
provides	O
ways	O
to	O
manipulate	O
reusable	O
components	O
.	O
</s>
<s>
Before	O
the	O
release	O
of	O
OpenJDK	B-Language
,	O
the	O
JDK	B-Language
was	O
based	O
on	O
a	O
proprietary	B-Application
license	I-Application
.	O
</s>
<s>
Following	O
their	O
promise	O
to	O
release	O
a	O
fully	O
buildable	O
JDK	B-Language
based	O
on	O
almost	O
completely	O
free	O
and	O
open-source	B-License
code	O
in	O
the	O
first	O
half	O
of	O
2007	O
,	O
Sun	O
released	O
the	O
complete	O
source	O
code	O
of	O
the	O
Class	O
Library	O
under	O
the	O
GPL	B-License
on	O
May	O
8	O
,	O
2007	O
,	O
except	O
some	O
limited	O
parts	O
that	O
were	O
licensed	O
by	O
Sun	O
from	O
third	O
parties	O
who	O
did	O
not	O
want	O
their	O
code	O
to	O
be	O
released	O
under	O
an	O
open-source	B-License
license	O
.	O
</s>
<s>
Sun	O
's	O
goal	O
was	O
to	O
replace	O
the	O
parts	O
that	O
remain	O
proprietary	B-Application
and	O
closed	B-Application
source	I-Application
with	O
alternative	O
implementations	O
and	O
make	O
the	O
Class	O
Library	O
completely	O
free	O
and	O
open	B-License
source	I-License
.	O
</s>
<s>
Until	O
December	O
2010	O
,	O
the	O
remaining	O
encumbered	O
part	O
of	O
the	O
JDK	B-Language
was	O
made	O
available	O
by	O
Sun	O
then	O
Oracle	B-Application
as	O
Binary	O
Plugs	O
which	O
were	O
required	O
to	O
build	O
the	O
JDK	B-Language
but	O
not	O
necessary	O
to	O
run	O
it	O
.	O
</s>
<s>
,	O
the	O
only	O
part	O
of	O
the	O
Class	O
library	O
that	O
remained	O
proprietary	B-Application
and	O
closed-source	B-Application
(	O
4%	O
for	O
OpenJDK	B-Language
7	O
,	O
and	O
less	O
than	O
1%	O
and	O
OpenJDK	B-Language
6	O
)	O
was	O
the	O
SNMP	B-Protocol
implementation	O
.	O
</s>
<s>
Since	O
the	O
first	O
May	O
2007	O
release	O
,	O
Sun	O
,	O
with	O
the	O
help	O
of	O
the	O
community	O
,	O
released	O
as	O
open-source	B-License
or	O
replaced	O
with	O
open-source	B-License
alternatives	O
almost	O
all	O
the	O
encumbered	O
code	O
:	O
</s>
<s>
All	O
the	O
audio	O
engine	O
code	O
,	O
including	O
the	O
software	O
synthesizer	O
,	O
became	O
open	B-License
source	I-License
.	O
</s>
<s>
The	O
closed-source	B-Application
software	I-Application
synthesizer	O
has	O
been	O
replaced	O
by	O
a	O
new	O
synthesizer	O
developed	O
specifically	O
for	O
OpenJDK	B-Language
called	O
Gervill	O
,	O
</s>
<s>
All	O
cryptography	O
classes	O
were	O
released	O
as	O
open-source	B-License
,	O
</s>
<s>
The	O
native	O
color	O
management	O
uses	O
open-source	B-License
LittleCMS	B-Application
.	O
</s>
<s>
There	O
is	O
a	O
pluggable	O
layer	O
in	O
the	O
JDK	B-Language
,	O
so	O
that	O
the	O
commercial	O
release	O
of	O
Java	B-Device
can	O
use	O
the	O
original	O
,	O
proprietary	B-Application
color	O
management	O
system	O
and	O
OpenJDK	B-Language
can	O
use	O
LittleCMS	B-Application
.	O
</s>
<s>
The	O
anti-aliasing	B-Algorithm
graphics	O
rasterizer	O
code	O
uses	O
the	O
open	B-License
source	I-License
Pisces	O
renderer	O
used	O
in	O
the	O
phoneME	B-Language
project	O
.	O
</s>
<s>
The	O
JavaScript	B-Language
plugin	O
is	O
open	B-License
source	I-License
(	O
the	O
JavaScript	B-Language
engine	I-Language
itself	O
was	O
open	B-License
source	I-License
from	O
the	O
beginning	O
)	O
.	O
</s>
<s>
Beginning	O
in	O
December	O
2010	O
,	O
all	O
the	O
so-called	O
binary	O
plugs	O
were	O
replaced	O
by	O
open	B-License
source	I-License
replacements	O
,	O
making	O
the	O
entire	O
JDK	B-Language
open	O
.	O
</s>
<s>
GNU	B-Language
Classpath	I-Language
is	O
the	O
other	O
main	O
free	O
software	O
class	O
library	O
for	O
Java	B-Device
.	O
</s>
<s>
Contrary	O
to	O
other	O
implementations	O
,	O
it	O
only	O
implements	B-Language
the	O
Class	O
Library	O
,	O
and	O
is	O
used	O
by	O
many	O
free	B-Language
Java	I-Language
runtimes	I-Language
(	O
like	O
Kaffe	B-Language
,	O
SableVM	B-Language
,	O
JamVM	B-Language
)	O
.	O
</s>
<s>
Apache	B-Application
Harmony	I-Application
was	O
another	O
free	O
software	O
class	O
library	O
.	O
</s>
<s>
Its	O
aim	O
was	O
to	O
implement	O
the	O
other	O
parts	O
of	O
the	O
Java	B-Device
stack	O
(	O
Virtual	B-Language
Machine	I-Language
,	O
Compiler	B-Language
,	O
and	O
other	O
tools	O
required	O
for	O
any	O
Java	B-Language
implementation	I-Language
)	O
.	O
</s>
