<s>
Java	B-Device
is	O
a	O
high-level	B-Language
,	O
class-based	B-Application
,	O
object-oriented	B-Language
programming	I-Language
language	I-Language
that	O
is	O
designed	O
to	O
have	O
as	O
few	O
implementation	O
dependencies	B-Application
as	O
possible	O
.	O
</s>
<s>
It	O
is	O
a	O
general-purpose	B-General_Concept
programming	O
language	O
intended	O
to	O
let	O
programmers	B-Application
write	O
once	O
,	O
run	O
anywhere	O
(	O
WORA	O
)	O
,	O
meaning	O
that	O
compiled	B-Language
Java	B-Language
code	I-Language
can	O
run	O
on	O
all	O
platforms	B-Device
that	O
support	O
Java	B-Device
without	O
the	O
need	O
to	O
recompile	B-Language
.	O
</s>
<s>
Java	B-Device
applications	O
are	O
typically	O
compiled	B-Language
to	O
bytecode	B-Language
that	O
can	O
run	O
on	O
any	O
Java	B-Language
virtual	I-Language
machine	I-Language
(	O
JVM	B-Language
)	O
regardless	O
of	O
the	O
underlying	O
computer	B-General_Concept
architecture	I-General_Concept
.	O
</s>
<s>
The	O
syntax	O
of	O
Java	B-Device
is	O
similar	O
to	O
C	B-Language
and	O
C++	B-Language
,	O
but	O
has	O
fewer	O
low-level	B-Language
facilities	O
than	O
either	O
of	O
them	O
.	O
</s>
<s>
The	O
Java	B-Language
runtime	I-Language
provides	O
dynamic	B-Language
capabilities	O
(	O
such	O
as	O
reflection	B-Language
and	O
runtime	O
code	O
modification	O
)	O
that	O
are	O
typically	O
not	O
available	O
in	O
traditional	O
compiled	B-Language
languages	O
.	O
</s>
<s>
,	O
Java	B-Device
was	O
one	O
of	O
the	O
most	O
popular	O
programming	O
languages	O
in	O
use	O
according	O
to	O
GitHub	B-Application
,	O
particularly	O
for	O
client	B-Operating_System
–	I-Operating_System
server	I-Operating_System
web	B-Application
applications	I-Application
,	O
with	O
a	O
reported	O
9	O
million	O
developers	B-Application
.	O
</s>
<s>
Java	B-Device
was	O
originally	O
developed	O
by	O
James	O
Gosling	O
at	O
Sun	O
Microsystems	O
.	O
</s>
<s>
It	O
was	O
released	O
in	O
May	O
1995	O
as	O
a	O
core	O
component	O
of	O
Sun	O
Microsystems	O
 '	O
Java	B-Device
platform	I-Device
.	O
</s>
<s>
The	O
original	O
and	O
reference	O
implementation	O
Java	B-Language
compilers	I-Language
,	O
virtual	B-Architecture
machines	I-Architecture
,	O
and	O
class	B-Library
libraries	I-Library
were	O
originally	O
released	O
by	O
Sun	O
under	O
proprietary	B-Application
licenses	I-Application
.	O
</s>
<s>
As	O
of	O
May	O
2007	O
,	O
in	O
compliance	O
with	O
the	O
specifications	O
of	O
the	O
Java	B-Language
Community	I-Language
Process	I-Language
,	O
Sun	O
had	O
relicensed	O
most	O
of	O
its	O
Java	B-Device
technologies	I-Device
under	O
the	O
GPL-2.0-only	B-License
license	O
.	O
</s>
<s>
Oracle	B-Application
offers	O
its	O
own	O
HotSpot	B-Language
Java	B-Language
Virtual	I-Language
Machine	I-Language
,	O
however	O
the	O
official	O
reference	O
implementation	O
is	O
the	O
OpenJDK	B-Language
JVM	B-Language
which	O
is	O
free	B-License
open-source	I-License
software	I-License
and	O
used	O
by	O
most	O
developers	B-Application
and	O
is	O
the	O
default	O
JVM	B-Language
for	O
almost	O
all	O
Linux	B-Operating_System
distributions	O
.	O
</s>
<s>
,	O
Java	B-Device
20	O
is	O
the	O
latest	O
version	O
,	O
while	O
Java	B-Device
17	O
,	O
11	O
and	O
8	O
are	O
the	O
current	O
long-term	O
support	O
(	O
LTS	O
)	O
versions	O
.	O
</s>
<s>
James	O
Gosling	O
,	O
Mike	O
Sheridan	O
,	O
and	O
Patrick	O
Naughton	O
initiated	O
the	O
Java	B-Language
language	I-Language
project	O
in	O
June	O
1991	O
.	O
</s>
<s>
Java	B-Device
was	O
originally	O
designed	O
for	O
interactive	O
television	O
,	O
but	O
it	O
was	O
too	O
advanced	O
for	O
the	O
digital	O
cable	O
television	O
industry	O
at	O
the	O
time	O
.	O
</s>
<s>
The	O
language	O
was	O
initially	O
called	O
Oak	B-Language
after	O
an	O
oak	B-Language
tree	O
that	O
stood	O
outside	O
Gosling	O
's	O
office	O
.	O
</s>
<s>
Later	O
the	O
project	O
went	O
by	O
the	O
name	O
Green	O
and	O
was	O
finally	O
renamed	O
Java	B-Device
,	O
from	O
Java	B-Device
coffee	O
,	O
a	O
type	O
of	O
coffee	O
from	O
Indonesia	O
.	O
</s>
<s>
Gosling	O
designed	O
Java	B-Device
with	O
a	O
C/C	O
++	O
-style	O
syntax	O
that	O
system	O
and	O
application	O
programmers	B-Application
would	O
find	O
familiar	O
.	O
</s>
<s>
Sun	O
Microsystems	O
released	O
the	O
first	O
public	O
implementation	O
as	O
Java	B-Device
1.0	O
in	O
1996	O
.	O
</s>
<s>
It	O
promised	O
write	O
once	O
,	O
run	O
anywhere	O
(	O
WORA	O
)	O
functionality	O
,	O
providing	O
no-cost	O
run-times	O
on	O
popular	O
platforms	B-Device
.	O
</s>
<s>
Major	O
web	B-Application
browsers	I-Application
soon	O
incorporated	O
the	O
ability	O
to	O
run	O
Java	B-Application
applets	I-Application
within	O
web	O
pages	O
,	O
and	O
Java	B-Device
quickly	O
became	O
popular	O
.	O
</s>
<s>
The	O
Java	B-Device
1.0	O
compiler	B-Language
was	O
re-written	O
in	B-Application
Java	I-Application
by	O
Arthur	O
van	O
Hoff	O
to	O
comply	O
strictly	O
with	O
the	O
Java	B-Device
1.0	O
language	O
specification	O
.	O
</s>
<s>
With	O
the	O
advent	O
of	O
Java	B-Device
2	O
(	O
released	O
initially	O
as	O
J2SE	B-Language
1.2	O
in	O
December	O
1998	O
1999	O
)	O
,	O
new	O
versions	O
had	O
multiple	O
configurations	O
built	O
for	O
different	O
types	O
of	O
platforms	B-Device
.	O
</s>
<s>
J2EE	B-Language
included	O
technologies	O
and	O
APIs	B-Application
for	O
enterprise	O
applications	O
typically	O
run	O
in	O
server	O
environments	O
,	O
while	O
J2ME	B-Language
featured	O
APIs	B-Application
optimized	O
for	O
mobile	O
applications	O
.	O
</s>
<s>
The	O
desktop	O
version	O
was	O
renamed	O
J2SE	B-Language
.	O
</s>
<s>
In	O
2006	O
,	O
for	O
marketing	O
purposes	O
,	O
Sun	O
renamed	O
new	O
J2	O
versions	O
as	O
Java	B-Language
EE	I-Language
,	O
Java	B-Language
ME	I-Language
,	O
and	O
Java	B-Language
SE	I-Language
,	O
respectively	O
.	O
</s>
<s>
In	O
1997	O
,	O
Sun	O
Microsystems	O
approached	O
the	O
ISO/IEC	O
JTC	O
1	O
standards	O
body	O
and	O
later	O
the	O
Ecma	O
International	O
to	O
formalize	O
Java	B-Device
,	O
but	O
it	O
soon	O
withdrew	O
from	O
the	O
process	O
.	O
</s>
<s>
Java	B-Device
remains	O
a	O
de	O
facto	O
standard	O
,	O
controlled	O
through	O
the	O
Java	B-Language
Community	I-Language
Process	I-Language
.	O
</s>
<s>
At	O
one	O
time	O
,	O
Sun	O
made	O
most	O
of	O
its	O
Java	B-Device
implementations	O
available	O
without	O
charge	O
,	O
despite	O
their	O
proprietary	B-Application
software	I-Application
status	O
.	O
</s>
<s>
Sun	O
generated	O
revenue	O
from	O
Java	B-Device
through	O
the	O
selling	O
of	O
licenses	O
for	O
specialized	O
products	O
such	O
as	O
the	O
Java	B-Language
Enterprise	I-Language
System	O
.	O
</s>
<s>
On	O
November	O
13	O
,	O
2006	O
,	O
Sun	O
released	O
much	O
of	O
its	O
Java	B-Language
virtual	I-Language
machine	I-Language
(	O
JVM	B-Language
)	O
as	O
free	B-License
and	I-License
open-source	I-License
software	I-License
(	O
FOSS	B-License
)	O
,	O
under	O
the	O
terms	O
of	O
the	O
GPL-2.0-only	B-License
license	O
.	O
</s>
<s>
On	O
May	O
8	O
,	O
2007	O
,	O
Sun	O
finished	O
the	O
process	O
,	O
making	O
all	O
of	O
its	O
JVM	B-Language
's	O
core	O
code	O
available	O
under	O
free	O
software/open	O
-source	O
distribution	O
terms	O
,	O
aside	O
from	O
a	O
small	O
portion	O
of	O
code	O
to	O
which	O
Sun	O
did	O
not	O
hold	O
the	O
copyright	O
.	O
</s>
<s>
Sun	O
's	O
vice-president	O
Rich	O
Green	O
said	O
that	O
Sun	O
's	O
ideal	O
role	O
with	O
regard	O
to	O
Java	B-Device
was	O
as	O
an	O
evangelist	O
.	O
</s>
<s>
Following	O
Oracle	B-Application
Corporation	I-Application
's	O
acquisition	O
of	O
Sun	O
Microsystems	O
in	O
2009	O
–	O
10	O
,	O
Oracle	B-Application
has	O
described	O
itself	O
as	O
the	O
steward	O
of	O
Java	B-Device
technology	I-Device
with	O
a	O
relentless	O
commitment	O
to	O
fostering	O
a	O
community	O
of	O
participation	O
and	O
transparency	O
.	O
</s>
<s>
This	O
did	O
not	O
prevent	O
Oracle	B-Application
from	O
filing	O
a	O
lawsuit	O
against	O
Google	O
shortly	O
after	O
that	O
for	O
using	O
Java	B-Device
inside	O
the	O
Android	B-Application
SDK	I-Application
(	O
see	O
the	O
Android	B-Application
section	O
)	O
.	O
</s>
<s>
On	O
April	O
2	O
,	O
2010	O
,	O
James	O
Gosling	O
resigned	O
from	O
Oracle	B-Application
.	O
</s>
<s>
In	O
January	O
2016	O
,	O
Oracle	B-Application
announced	O
that	O
Java	B-Device
run-time	O
environments	O
based	O
on	O
JDK	B-Language
9	O
will	O
discontinue	O
the	O
browser	B-Application
plugin	O
.	O
</s>
<s>
Java	B-Device
software	O
runs	O
on	O
everything	O
from	O
laptops	O
to	O
data	B-Operating_System
centers	I-Operating_System
,	O
game	B-Device
consoles	I-Device
to	O
scientific	O
supercomputers	B-Architecture
.	O
</s>
<s>
Oracle	B-Application
(	O
and	O
others	O
)	O
highly	O
recommend	O
uninstalling	O
outdated	O
and	O
unsupported	O
versions	O
of	O
Java	B-Device
,	O
due	O
to	O
unresolved	O
security	O
issues	O
in	O
older	O
versions	O
.	O
</s>
<s>
There	O
were	O
five	O
primary	O
goals	O
in	O
the	O
creation	O
of	O
the	O
Java	B-Language
language	I-Language
:	O
</s>
<s>
It	O
must	O
be	O
simple	O
,	O
object-oriented	B-Language
,	O
and	O
familiar	O
.	O
</s>
<s>
It	O
must	O
be	O
robust	B-Application
and	O
secure	O
.	O
</s>
<s>
It	O
must	O
be	O
interpreted	B-Application
,	O
threaded	O
,	O
and	O
dynamic	B-Language
.	O
</s>
<s>
,	O
Java	B-Device
8	O
,	O
11	O
and	O
17	O
are	O
supported	O
as	O
Long-Term	O
Support	O
(	O
LTS	O
)	O
versions	O
.	O
</s>
<s>
Oracle	B-Application
released	O
the	O
last	O
zero-cost	O
public	O
update	O
for	O
the	O
legacy	B-Device
version	O
Java	B-Device
8	O
LTS	O
in	O
January	O
2019	O
for	O
commercial	O
use	O
,	O
although	O
it	O
will	O
otherwise	O
still	O
support	O
Java8	O
with	O
public	O
updates	O
for	O
personal	O
use	O
indefinitely	O
.	O
</s>
<s>
Other	O
vendors	O
have	O
begun	O
to	O
offer	O
zero-cost	O
builds	O
of	O
OpenJDK	B-Language
18	O
and	O
8	O
,	O
11	O
and	O
17	O
that	O
are	O
still	O
receiving	O
security	O
and	O
other	O
upgrades	O
.	O
</s>
<s>
Major	O
release	O
versions	O
of	O
Java	B-Device
,	O
along	O
with	O
their	O
release	O
dates	O
:	O
</s>
<s>
Sun	O
has	O
defined	O
and	O
supports	O
four	O
editions	O
of	O
Java	B-Device
targeting	O
different	O
application	O
environments	O
and	O
segmented	O
many	O
of	O
its	O
APIs	B-Application
so	O
that	O
they	O
belong	O
to	O
one	O
of	O
the	O
platforms	B-Device
.	O
</s>
<s>
The	O
platforms	B-Device
are	O
:	O
</s>
<s>
Java	B-Language
Card	I-Language
for	O
smart-cards	O
.	O
</s>
<s>
Java	B-Language
Platform	I-Language
,	I-Language
Micro	I-Language
Edition	I-Language
(	O
Java	B-Language
ME	I-Language
)	O
–	O
targeting	O
environments	O
with	O
limited	O
resources	O
.	O
</s>
<s>
Java	B-Language
Platform	I-Language
,	I-Language
Standard	I-Language
Edition	I-Language
(	O
Java	B-Language
SE	I-Language
)	O
–	O
targeting	O
workstation	O
environments	O
.	O
</s>
<s>
Java	B-Language
Platform	I-Language
,	I-Language
Enterprise	I-Language
Edition	I-Language
(	O
Java	B-Language
EE	I-Language
)	O
–	O
targeting	O
large	O
distributed	O
enterprise	O
or	O
Internet	O
environments	O
.	O
</s>
<s>
The	O
classes	O
in	O
the	O
Java	B-Language
APIs	I-Language
are	O
organized	O
into	O
separate	O
groups	O
called	O
packages	B-Language
.	O
</s>
<s>
Each	O
package	O
contains	O
a	O
set	O
of	O
related	O
interfaces	B-Language
,	O
classes	O
,	O
subpackages	O
and	O
exceptions	B-General_Concept
.	O
</s>
<s>
Sun	O
also	O
provided	O
an	O
edition	O
called	O
Personal	B-Language
Java	I-Language
that	O
has	O
been	O
superseded	O
by	O
later	O
,	O
standards-based	O
Java	B-Language
ME	I-Language
configuration-profile	O
pairings	O
.	O
</s>
<s>
One	O
design	O
goal	O
of	O
Java	B-Device
is	O
portability	B-Architecture
,	O
which	O
means	O
that	O
programs	O
written	O
for	O
the	O
Java	B-Device
platform	I-Device
must	O
run	O
similarly	O
on	O
any	O
combination	O
of	O
hardware	O
and	O
operating	O
system	O
with	O
adequate	O
run	O
time	O
support	O
.	O
</s>
<s>
This	O
is	O
achieved	O
by	O
compiling	B-Language
the	O
Java	B-Language
language	I-Language
code	O
to	O
an	O
intermediate	O
representation	O
called	O
Java	B-Language
bytecode	I-Language
,	O
instead	O
of	O
directly	O
to	O
architecture-specific	O
machine	B-Language
code	I-Language
.	O
</s>
<s>
Java	B-Language
bytecode	I-Language
instructions	O
are	O
analogous	O
to	O
machine	B-Language
code	I-Language
,	O
but	O
they	O
are	O
intended	O
to	O
be	O
executed	O
by	O
a	O
virtual	B-Architecture
machine	I-Architecture
(	O
VM	O
)	O
written	O
specifically	O
for	O
the	O
host	O
hardware	O
.	O
</s>
<s>
End-users	O
commonly	O
use	O
a	O
Java	B-Language
Runtime	I-Language
Environment	I-Language
(	O
JRE	O
)	O
installed	O
on	O
their	O
device	O
for	O
standalone	O
Java	B-Device
applications	O
or	O
a	O
web	B-Application
browser	I-Application
for	O
Java	B-Application
applets	I-Application
.	O
</s>
<s>
Standard	B-Library
libraries	I-Library
provide	O
a	O
generic	B-Language
way	O
to	O
access	O
host-specific	O
features	O
such	O
as	O
graphics	O
,	O
threading	B-Operating_System
,	O
and	O
networking	B-Architecture
.	O
</s>
<s>
The	O
use	O
of	O
universal	O
bytecode	B-Language
makes	O
porting	O
simple	O
.	O
</s>
<s>
However	O
,	O
the	O
overhead	O
of	O
interpreting	B-Application
bytecode	B-Language
into	O
machine	B-Language
instructions	I-Language
made	O
interpreted	B-Application
programs	O
almost	O
always	O
run	O
more	O
slowly	O
than	O
native	B-Language
executables	B-Application
.	O
</s>
<s>
Just-in-time	O
(	O
JIT	O
)	O
compilers	B-Language
that	O
compile	B-Language
byte-codes	O
to	O
machine	B-Language
code	I-Language
during	O
runtime	O
were	O
introduced	O
from	O
an	O
early	O
stage	O
.	O
</s>
<s>
Java	B-Device
's	O
Hotspot	B-Language
compiler	B-Language
is	O
actually	O
two	O
compilers	B-Language
in	O
one	O
;	O
and	O
with	O
GraalVM	B-Language
(	O
included	O
in	O
e.g.	O
</s>
<s>
Java	B-Device
11	O
,	O
but	O
removed	O
as	O
of	O
Java	B-Device
16	O
)	O
allowing	O
tiered	O
compilation	B-Language
.	O
</s>
<s>
Java	B-Device
itself	O
is	O
platform-independent	O
and	O
is	O
adapted	O
to	O
the	O
particular	O
platform	O
it	O
is	O
to	O
run	O
on	O
by	O
a	O
Java	B-Language
virtual	I-Language
machine	I-Language
(	O
JVM	B-Language
)	O
for	O
it	O
,	O
which	O
translates	O
the	O
Java	B-Language
bytecode	I-Language
into	O
the	O
platform	O
's	O
machine	B-Language
language	I-Language
.	O
</s>
<s>
Programs	O
written	O
in	B-Application
Java	I-Application
have	O
a	O
reputation	O
for	O
being	O
slower	O
and	O
requiring	O
more	O
memory	O
than	O
those	O
written	O
in	O
C++	B-Language
.	O
</s>
<s>
However	O
,	O
Java	B-Device
programs	O
 '	O
execution	O
speed	O
improved	O
significantly	O
with	O
the	O
introduction	O
of	O
just-in-time	O
compilation	B-Language
in	O
1997/1998	O
for	O
Java	B-Device
1.1	O
,	O
the	O
addition	O
of	O
language	O
features	O
supporting	O
better	O
code	O
analysis	O
(	O
such	O
as	O
inner	O
classes	O
,	O
the	O
StringBuilder	O
class	O
,	O
optional	O
assertions	O
,	O
etc	O
.	O
</s>
<s>
)	O
,	O
and	O
optimizations	O
in	O
the	O
Java	B-Language
virtual	I-Language
machine	I-Language
,	O
such	O
as	O
HotSpot	B-Language
becoming	O
Sun	O
's	O
default	O
JVM	B-Language
in	O
2000	O
.	O
</s>
<s>
With	O
Java1.5	O
,	O
the	O
performance	O
was	O
improved	O
with	O
the	O
addition	O
of	O
the	O
java.util.concurrent	O
package	O
,	O
including	O
lock-free	B-Operating_System
implementations	O
of	O
the	O
ConcurrentMaps	B-Operating_System
and	O
other	O
multi-core	O
collections	O
,	O
and	O
it	O
was	O
improved	O
further	O
with	O
Java1.6	O
.	O
</s>
<s>
Some	O
platforms	B-Device
offer	O
direct	O
hardware	O
support	O
for	O
Java	B-Device
;	O
there	O
are	O
micro	O
controllers	O
that	O
can	O
run	O
Java	B-Language
bytecode	I-Language
in	O
hardware	O
instead	O
of	O
a	O
software	O
Java	B-Language
virtual	I-Language
machine	I-Language
,	O
and	O
some	O
ARM-based	O
processors	O
could	O
have	O
hardware	O
support	O
for	O
executing	O
Java	B-Language
bytecode	I-Language
through	O
their	O
Jazelle	B-Language
option	O
,	O
though	O
support	O
has	O
mostly	O
been	O
dropped	O
in	O
current	O
implementations	O
of	O
ARM	B-Architecture
.	O
</s>
<s>
Java	B-Device
uses	O
an	O
automatic	B-General_Concept
garbage	I-General_Concept
collector	I-General_Concept
to	O
manage	O
memory	O
in	O
the	O
object	O
lifecycle	O
.	O
</s>
<s>
The	O
programmer	B-Application
determines	O
when	O
objects	O
are	O
created	O
,	O
and	O
the	O
Java	B-Language
runtime	I-Language
is	O
responsible	O
for	O
recovering	O
the	O
memory	O
once	O
objects	O
are	O
no	O
longer	O
in	O
use	O
.	O
</s>
<s>
Once	O
no	O
references	O
to	O
an	O
object	O
remain	O
,	O
the	O
unreachable	B-General_Concept
memory	I-General_Concept
becomes	O
eligible	O
to	O
be	O
freed	O
automatically	O
by	O
the	O
garbage	B-General_Concept
collector	I-General_Concept
.	O
</s>
<s>
Something	O
similar	O
to	O
a	O
memory	B-Error_Name
leak	I-Error_Name
may	O
still	O
occur	O
if	O
a	O
programmer	B-Application
's	O
code	O
holds	O
a	O
reference	O
to	O
an	O
object	O
that	O
is	O
no	O
longer	O
needed	O
,	O
typically	O
when	O
objects	O
that	O
are	O
no	O
longer	O
needed	O
are	O
stored	O
in	O
containers	O
that	O
are	O
still	O
in	O
use	O
.	O
</s>
<s>
One	O
of	O
the	O
ideas	O
behind	O
Java	B-Device
's	O
automatic	B-General_Concept
memory	I-General_Concept
management	I-General_Concept
model	O
is	O
that	O
programmers	B-Application
can	O
be	O
spared	O
the	O
burden	O
of	O
having	O
to	O
perform	O
manual	O
memory	O
management	O
.	O
</s>
<s>
In	O
some	O
languages	O
,	O
memory	O
for	O
the	O
creation	O
of	O
objects	O
is	O
implicitly	O
allocated	O
on	O
the	O
stack	B-Application
or	O
explicitly	O
allocated	O
and	O
deallocated	O
from	O
the	O
heap	O
.	O
</s>
<s>
In	O
the	O
latter	O
case	O
,	O
the	O
responsibility	O
of	O
managing	O
memory	O
resides	O
with	O
the	O
programmer	B-Application
.	O
</s>
<s>
If	O
the	O
program	O
does	O
not	O
deallocate	O
an	O
object	O
,	O
a	O
memory	B-Error_Name
leak	I-Error_Name
occurs	O
.	O
</s>
<s>
This	O
can	O
be	O
partially	O
remedied	O
by	O
the	O
use	O
of	O
smart	B-Language
pointers	I-Language
,	O
but	O
these	O
add	O
overhead	O
and	O
complexity	O
.	O
</s>
<s>
Note	O
that	O
garbage	B-General_Concept
collection	I-General_Concept
does	O
not	O
prevent	O
logical	B-General_Concept
memory	I-General_Concept
leaks	O
,	O
i.e.	O
</s>
<s>
Garbage	B-General_Concept
collection	I-General_Concept
may	O
happen	O
at	O
any	O
time	O
.	O
</s>
<s>
Explicit	O
memory	O
management	O
is	O
not	O
possible	O
in	B-Application
Java	I-Application
.	O
</s>
<s>
Java	B-Device
does	O
not	O
support	O
C/C	O
++	O
style	O
pointer	O
arithmetic	O
,	O
where	O
object	O
addresses	O
can	O
be	O
arithmetically	O
manipulated	O
(	O
e.g.	O
</s>
<s>
This	O
allows	O
the	O
garbage	B-General_Concept
collector	I-General_Concept
to	O
relocate	O
referenced	O
objects	O
and	O
ensures	O
type	B-Language
safety	I-Language
and	O
security	O
.	O
</s>
<s>
As	O
in	O
C++	B-Language
and	O
some	O
other	O
object-oriented	B-Language
languages	I-Language
,	O
variables	O
of	O
Java	B-Device
's	O
primitive	O
data	O
types	O
are	O
either	O
stored	O
directly	O
in	O
fields	O
(	O
for	O
objects	O
)	O
or	O
on	O
the	O
stack	B-Application
(	O
for	O
methods	O
)	O
rather	O
than	O
on	O
the	O
heap	O
,	O
as	O
is	O
commonly	O
true	O
for	O
non-primitive	O
data	O
types	O
(	O
but	O
see	O
escape	O
analysis	O
)	O
.	O
</s>
<s>
This	O
was	O
a	O
conscious	O
decision	O
by	O
Java	B-Device
's	O
designers	O
for	O
performance	O
reasons	O
.	O
</s>
<s>
Java	B-Device
contains	O
multiple	O
types	O
of	O
garbage	B-General_Concept
collectors	I-General_Concept
.	O
</s>
<s>
Since	O
Java	B-Device
9	O
,	O
HotSpot	B-Language
uses	O
the	O
Garbage	B-Language
First	I-Language
Garbage	I-Language
Collector	I-Language
(	O
G1GC	O
)	O
as	O
the	O
default	O
.	O
</s>
<s>
However	O
,	O
there	O
are	O
also	O
several	O
other	O
garbage	B-General_Concept
collectors	I-General_Concept
that	O
can	O
be	O
used	O
to	O
manage	O
the	O
heap	O
.	O
</s>
<s>
For	O
most	O
applications	O
in	B-Application
Java	I-Application
,	O
G1GC	O
is	O
sufficient	O
.	O
</s>
<s>
Previously	O
,	O
the	O
was	O
used	O
in	B-Application
Java	I-Application
8	O
.	O
</s>
<s>
Having	O
solved	O
the	O
memory	O
management	O
problem	O
does	O
not	O
relieve	O
the	O
programmer	B-Application
of	O
the	O
burden	O
of	O
handling	O
properly	O
other	O
kinds	O
of	O
resources	O
,	O
like	O
network	O
or	O
database	O
connections	O
,	O
file	O
handles	O
,	O
etc.	O
,	O
especially	O
in	O
the	O
presence	O
of	O
exceptions	B-General_Concept
.	O
</s>
<s>
The	O
syntax	O
of	O
Java	B-Device
is	O
largely	O
influenced	O
by	O
C++	B-Language
and	O
C	B-Language
.	O
Unlike	O
C++	B-Language
,	O
which	O
combines	O
the	O
syntax	O
for	O
structured	O
,	O
generic	B-Language
,	O
and	O
object-oriented	B-Language
programming	I-Language
,	O
Java	B-Device
was	O
built	O
almost	O
exclusively	O
as	O
an	O
object-oriented	B-Language
language	I-Language
.	O
</s>
<s>
Java	B-Device
reuses	O
some	O
popular	O
aspects	O
of	O
C++	B-Language
(	O
such	O
as	O
the	O
method	O
)	O
.	O
</s>
<s>
Unlike	O
C++	B-Language
,	O
Java	B-Device
does	O
not	O
support	O
operator	O
overloading	O
or	O
multiple	B-Application
inheritance	I-Application
for	O
classes	O
,	O
though	O
multiple	B-Application
inheritance	I-Application
is	O
supported	O
for	O
interfaces	B-Language
.	O
</s>
<s>
Java	B-Device
uses	O
comments	O
similar	O
to	O
those	O
of	O
C++	B-Language
.	O
</s>
<s>
There	O
are	O
three	O
different	O
styles	O
of	O
comments	O
:	O
a	O
single	O
line	O
style	O
marked	O
with	O
two	O
slashes	O
(//	O
)	O
,	O
a	O
multiple	O
line	O
style	O
opened	O
with	O
/	O
*	O
and	O
closed	O
with	O
*	O
/	O
,	O
and	O
the	O
Javadoc	B-Language
commenting	O
style	O
opened	O
with	O
/	O
**	O
and	O
closed	O
with	O
*	O
/	O
.	O
</s>
<s>
The	O
Javadoc	B-Language
style	O
of	O
commenting	O
allows	O
the	O
user	O
to	O
run	O
the	O
Javadoc	B-Language
executable	B-Application
to	O
create	O
documentation	O
for	O
the	O
program	O
and	O
can	O
be	O
read	O
by	O
some	O
integrated	B-Application
development	I-Application
environments	I-Application
(	O
IDEs	O
)	O
such	O
as	O
Eclipse	B-Application
to	O
allow	O
developers	B-Application
to	O
access	O
documentation	O
within	O
the	O
IDE	O
.	O
</s>
<s>
The	O
traditional	O
Hello	O
world	O
program	O
can	O
be	O
written	O
in	B-Application
Java	I-Application
as	O
:	O
</s>
<s>
All	O
source	O
files	O
must	O
be	O
named	O
after	O
the	O
public	O
class	O
they	O
contain	O
,	O
appending	O
the	O
suffix	O
.java	O
,	O
for	O
example	O
,	O
HelloWorldApp.java	O
.	O
</s>
<s>
It	O
must	O
first	O
be	O
compiled	B-Language
into	O
bytecode	B-Language
,	O
using	O
a	O
Java	B-Language
compiler	I-Language
,	O
producing	O
a	O
file	O
with	O
the	O
.class	B-Language
suffix	O
(	O
HelloWorldApp.class	O
,	O
in	O
this	O
case	O
)	O
.	O
</s>
<s>
The	O
Java	B-Device
source	O
file	O
may	O
only	O
contain	O
one	O
public	O
class	O
,	O
but	O
it	O
can	O
contain	O
multiple	O
classes	O
with	O
a	O
non-public	O
access	O
modifier	O
and	O
any	O
number	O
of	O
public	O
inner	O
classes	O
.	O
</s>
<s>
When	O
the	O
source	O
file	O
contains	O
multiple	O
classes	O
,	O
it	O
is	O
necessary	O
to	O
make	O
one	O
class	O
(	O
introduced	O
by	O
the	O
class	O
keyword	B-Language
)	O
public	O
(	O
preceded	O
by	O
the	O
public	O
keyword	B-Language
)	O
and	O
name	O
the	O
source	O
file	O
with	O
that	O
public	O
class	O
name	O
.	O
</s>
<s>
A	O
class	O
that	O
is	O
not	O
declared	O
public	O
may	O
be	O
stored	O
in	O
any	O
.java	O
file	O
.	O
</s>
<s>
The	O
compiler	B-Language
will	O
generate	O
a	O
class	B-Language
file	I-Language
for	O
each	O
class	O
defined	O
in	O
the	O
source	O
file	O
.	O
</s>
<s>
The	O
name	O
of	O
the	O
class	B-Language
file	I-Language
is	O
the	O
name	O
of	O
the	O
class	O
,	O
with	O
.class	B-Language
appended	O
.	O
</s>
<s>
For	O
class	B-Language
file	I-Language
generation	O
,	O
anonymous	O
classes	O
are	O
treated	O
as	O
if	O
their	O
name	O
were	O
the	O
concatenation	O
of	O
the	O
name	O
of	O
their	O
enclosing	O
class	O
,	O
a	O
$	O
,	O
and	O
an	O
integer	O
.	O
</s>
<s>
The	O
keyword	B-Language
public	O
denotes	O
that	O
a	O
method	O
can	O
be	O
called	O
from	O
code	O
in	O
other	O
classes	O
,	O
or	O
that	O
a	O
class	O
may	O
be	O
used	O
by	O
classes	O
outside	O
the	O
class	O
hierarchy	O
.	O
</s>
<s>
The	O
class	O
hierarchy	O
is	O
related	O
to	O
the	O
name	O
of	O
the	O
directory	O
in	O
which	O
the	O
.java	O
file	O
is	O
located	O
.	O
</s>
<s>
The	O
keyword	B-Language
static	O
in	O
front	O
of	O
a	O
method	O
indicates	O
a	O
static	O
method	O
,	O
which	O
is	O
associated	O
only	O
with	O
the	O
class	O
and	O
not	O
with	O
any	O
specific	O
instance	O
of	O
that	O
class	O
.	O
</s>
<s>
The	O
keyword	B-Language
void	O
indicates	O
that	O
the	O
main	O
method	O
does	O
not	O
return	O
any	O
value	O
to	O
the	O
caller	O
.	O
</s>
<s>
If	O
a	O
Java	B-Device
program	O
is	O
to	O
exit	O
with	O
an	O
error	O
code	O
,	O
it	O
must	O
call	O
System.exit( )	O
explicitly	O
.	O
</s>
<s>
The	O
method	O
name	O
main	O
is	O
not	O
a	O
keyword	B-Language
in	O
the	O
Java	B-Language
language	I-Language
.	O
</s>
<s>
It	O
is	O
simply	O
the	O
name	O
of	O
the	O
method	O
the	O
Java	B-Device
launcher	O
calls	O
to	O
pass	O
control	O
to	O
the	O
program	O
.	O
</s>
<s>
Java	B-Device
classes	O
that	O
run	O
in	O
managed	O
environments	O
such	O
as	O
applets	B-Application
and	O
Enterprise	B-Language
JavaBeans	I-Language
do	O
not	O
use	O
or	O
need	O
a	O
main( )	O
method	O
.	O
</s>
<s>
A	O
Java	B-Device
program	O
may	O
contain	O
multiple	O
classes	O
that	O
have	O
main	O
methods	O
,	O
which	O
means	O
that	O
the	O
VM	O
needs	O
to	O
be	O
explicitly	O
told	O
which	O
class	O
to	O
launch	O
from	O
.	O
</s>
<s>
Since	O
Java5	O
,	O
the	O
main	O
method	O
can	O
also	O
use	O
variable	B-Language
arguments	I-Language
,	O
in	O
the	O
form	O
of	O
public	O
static	O
void	O
main( 	O
String	O
...	O
args	O
)	O
,	O
allowing	O
the	O
main	O
method	O
to	O
be	O
invoked	O
with	O
an	O
arbitrary	O
number	O
of	O
String	O
arguments	O
.	O
</s>
<s>
The	O
Java	B-Device
launcher	O
launches	O
Java	B-Device
by	O
loading	O
a	O
given	O
class	O
(	O
specified	O
on	O
the	O
command	B-Application
line	I-Application
or	O
as	O
an	O
attribute	O
in	O
a	O
JAR	B-Language
)	O
and	O
starting	O
its	O
public	O
static	O
void	O
main( String[]	O
)	O
method	O
.	O
</s>
<s>
The	O
parameters	O
to	O
main	O
are	O
often	O
passed	O
by	O
means	O
of	O
a	O
command	B-Application
line	I-Application
.	O
</s>
<s>
Printing	O
is	O
part	O
of	O
a	O
Java	B-Device
standard	B-Library
library	I-Library
:	O
The	O
class	O
defines	O
a	O
public	O
static	O
field	O
called	O
.	O
</s>
<s>
The	O
out	O
object	O
is	O
an	O
instance	O
of	O
the	O
class	O
and	O
provides	O
many	O
methods	O
for	O
printing	O
data	O
to	O
standard	B-Operating_System
out	I-Operating_System
,	O
including	O
which	O
also	O
appends	O
a	O
new	O
line	O
to	O
the	O
passed	O
string	O
.	O
</s>
<s>
is	O
automatically	O
converted	O
to	O
a	O
String	O
object	O
by	O
the	O
compiler	B-Language
.	O
</s>
<s>
Java	B-Application
applets	I-Application
were	O
programs	O
that	O
were	O
embedded	O
in	O
other	O
applications	O
,	O
typically	O
in	O
a	O
Web	O
page	O
displayed	O
in	O
a	O
web	B-Application
browser	I-Application
.	O
</s>
<s>
The	O
Java	B-Application
applet	I-Application
API	B-Application
is	O
now	O
deprecated	O
since	O
Java9	O
in	O
2017	O
.	O
</s>
<s>
Java	B-Application
servlet	I-Application
technology	O
provides	O
Web	O
developers	B-Application
with	O
a	O
simple	O
,	O
consistent	O
mechanism	O
for	O
extending	O
the	O
functionality	O
of	O
a	O
Web	O
server	O
and	O
for	O
accessing	O
existing	O
business	O
systems	O
.	O
</s>
<s>
Servlets	B-Application
are	O
server-side	B-Application
Java	B-Language
EE	I-Language
components	O
that	O
generate	O
responses	O
to	O
requests	O
from	O
clients	B-Protocol
.	O
</s>
<s>
Most	O
of	O
the	O
time	O
,	O
this	O
means	O
generating	O
HTML	B-Language
pages	O
in	O
response	O
to	O
HTTP	B-Protocol
requests	I-Protocol
,	O
although	O
there	O
are	O
a	O
number	O
of	O
other	O
standard	O
servlet	B-Application
classes	O
available	O
,	O
for	O
example	O
for	O
WebSocket	B-Protocol
communication	O
.	O
</s>
<s>
The	B-Application
Java	I-Application
servlet	I-Application
API	I-Application
has	O
to	O
some	O
extent	O
been	O
superseded	O
(	O
but	O
still	O
used	O
under	O
the	O
hood	O
)	O
by	O
two	O
standard	O
Java	B-Device
technologies	I-Device
for	O
web	O
services	O
:	O
</s>
<s>
the	O
Java	B-Language
API	I-Language
for	I-Language
XML	I-Language
Web	I-Language
Services	I-Language
(	O
JAX-WS	B-Language
)	O
useful	O
for	O
SOAP	B-Application
Web	O
Services	O
.	O
</s>
<s>
Typical	O
implementations	O
of	O
these	O
APIs	B-Application
on	O
Application	O
Servers	O
or	O
Servlet	B-Application
Containers	O
use	O
a	O
standard	O
servlet	B-Application
for	O
handling	O
all	O
interactions	O
with	O
the	O
HTTP	B-Protocol
requests	I-Protocol
and	O
responses	O
that	O
delegate	O
to	O
the	O
web	O
service	O
methods	O
for	O
the	O
actual	O
business	O
logic	O
.	O
</s>
<s>
JavaServer	B-Language
Pages	I-Language
(	O
JSP	B-Language
)	O
are	O
server-side	B-Application
Java	B-Language
EE	I-Language
components	O
that	O
generate	O
responses	O
,	O
typically	O
HTML	B-Language
pages	O
,	O
to	O
HTTP	B-Protocol
requests	I-Protocol
from	O
clients	B-Protocol
.	O
</s>
<s>
JSPs	O
embed	O
Java	B-Language
code	I-Language
in	O
an	O
HTML	B-Language
page	O
by	O
using	O
the	O
special	O
delimiters	B-Algorithm
<% and %>	O
.	O
</s>
<s>
A	O
JSP	B-Language
is	O
compiled	B-Language
to	O
a	O
Java	B-Application
servlet	I-Application
,	O
a	O
Java	B-Device
application	O
in	O
its	O
own	O
right	O
,	O
the	O
first	O
time	O
it	O
is	O
accessed	O
.	O
</s>
<s>
After	O
that	O
,	O
the	O
generated	O
servlet	B-Application
creates	O
the	O
response	O
.	O
</s>
<s>
Swing	B-Language
is	O
a	O
graphical	B-Application
user	I-Application
interface	I-Application
library	B-Library
for	O
the	O
Java	B-Language
SE	I-Language
platform	I-Language
.	O
</s>
<s>
It	O
is	O
possible	O
to	O
specify	O
a	O
different	O
look	O
and	O
feel	O
through	O
the	O
pluggable	B-Language
look	I-Language
and	I-Language
feel	I-Language
system	O
of	O
Swing	B-Language
.	O
</s>
<s>
Clones	O
of	O
Windows	B-Application
,	O
GTK+	B-Application
,	O
and	O
Motif	B-Application
are	O
supplied	O
by	O
Sun	O
.	O
</s>
<s>
Apple	O
also	O
provides	O
an	O
Aqua	B-Application
look	O
and	O
feel	O
for	O
macOS	B-Application
.	O
</s>
<s>
Where	O
prior	O
implementations	O
of	O
these	O
looks	O
and	O
feels	O
may	O
have	O
been	O
considered	O
lacking	O
,	O
Swing	B-Language
in	B-Application
Java	I-Application
SE	O
6	O
addresses	O
this	O
problem	O
by	O
using	O
more	O
native	B-Language
GUI	B-Application
widget	O
drawing	O
routines	O
of	O
the	O
underlying	O
platforms	B-Device
.	O
</s>
<s>
JavaFX	B-Application
is	O
a	O
software	B-Device
platform	I-Device
for	O
creating	O
and	O
delivering	O
desktop	B-Application
applications	I-Application
,	O
as	O
well	O
as	O
rich	B-Application
web	I-Application
applications	I-Application
that	O
can	O
run	O
across	O
a	O
wide	O
variety	O
of	O
devices	O
.	O
</s>
<s>
JavaFX	B-Application
is	O
intended	O
to	O
replace	O
Swing	B-Language
as	O
the	O
standard	O
GUI	B-Application
library	B-Library
for	O
Java	B-Language
SE	I-Language
,	O
but	O
since	O
JDK	B-Language
11	O
JavaFX	B-Application
has	O
not	O
been	O
in	O
the	O
core	O
JDK	B-Language
and	O
instead	O
in	O
a	O
separate	O
module	O
.	O
</s>
<s>
JavaFX	B-Application
has	O
support	O
for	O
desktop	B-Device
computers	I-Device
and	O
web	B-Application
browsers	I-Application
on	O
Microsoft	B-Application
Windows	I-Application
,	O
Linux	B-Operating_System
,	O
and	O
macOS	B-Application
.	O
</s>
<s>
JavaFX	B-Application
does	O
not	O
have	O
support	O
for	O
native	B-Language
OS	O
look	O
and	O
feels	O
.	O
</s>
<s>
In	O
2004	O
,	O
generics	B-Language
were	O
added	O
to	O
the	O
Java	B-Language
language	I-Language
,	O
as	O
part	O
of	O
J2SE	B-Language
5.0	O
.	O
</s>
<s>
Prior	O
to	O
the	O
introduction	O
of	O
generics	B-Language
,	O
each	O
variable	O
declaration	O
had	O
to	O
be	O
of	O
a	O
specific	O
type	O
.	O
</s>
<s>
Either	O
the	O
container	O
operates	O
on	O
all	O
subtypes	O
of	O
a	O
class	O
or	O
interface	B-Language
,	O
usually	O
Object	O
,	O
or	O
a	O
different	O
container	O
class	O
has	O
to	O
be	O
created	O
for	O
each	O
contained	O
class	O
.	O
</s>
<s>
Generics	B-Language
allow	O
compile-time	O
type	O
checking	O
without	O
having	O
to	O
create	O
many	O
container	O
classes	O
,	O
each	O
containing	O
almost	O
identical	O
code	O
.	O
</s>
<s>
In	O
addition	O
to	O
enabling	O
more	O
efficient	O
code	O
,	O
certain	O
runtime	B-General_Concept
exceptions	I-General_Concept
are	O
prevented	O
from	O
occurring	O
,	O
by	O
issuing	O
compile-time	O
errors	O
.	O
</s>
<s>
If	O
Java	B-Device
prevented	O
all	O
runtime	O
type	O
errors	O
(	O
ClassCastExceptions	O
)	O
from	O
occurring	O
,	O
it	O
would	O
be	O
type	B-Language
safe	I-Language
.	O
</s>
<s>
In	O
2016	O
,	O
the	O
type	O
system	O
of	O
Java	B-Device
was	O
proven	O
unsound	O
in	O
that	O
it	O
is	O
possible	O
to	O
use	O
generics	B-Language
to	O
construct	O
classes	O
and	O
methods	O
that	O
allow	O
assignment	O
of	O
an	O
instance	O
one	O
class	O
to	O
a	O
variable	O
of	O
another	O
unrelated	O
class	O
.	O
</s>
<s>
Such	O
code	O
is	O
accepted	O
by	O
the	O
compiler	B-Language
,	O
but	O
fails	O
at	O
run	O
time	O
with	O
a	O
class	O
cast	O
exception	O
.	O
</s>
<s>
Criticisms	O
directed	O
at	O
Java	B-Device
include	O
the	O
implementation	O
of	O
generics	B-Language
,	O
speed	O
,	O
the	O
handling	O
of	O
unsigned	O
numbers	O
,	O
the	O
implementation	O
of	O
floating-point	O
arithmetic	O
,	O
and	O
a	O
history	O
of	O
security	O
vulnerabilities	O
in	O
the	O
primary	O
Java	B-Language
VM	I-Language
implementation	O
HotSpot	B-Language
.	O
</s>
<s>
The	O
Java	B-Library
Class	I-Library
Library	I-Library
is	O
the	O
standard	B-Library
library	I-Library
,	O
developed	O
to	O
support	O
application	O
development	O
in	B-Application
Java	I-Application
.	O
</s>
<s>
It	O
is	O
controlled	O
by	O
Oracle	B-Application
in	O
cooperation	O
with	O
others	O
through	O
the	O
Java	B-Language
Community	I-Language
Process	I-Language
program	O
.	O
</s>
<s>
Companies	O
or	O
individuals	O
participating	O
in	O
this	O
process	O
can	O
influence	O
the	O
design	O
and	O
development	O
of	O
the	O
APIs	B-Application
.	O
</s>
<s>
The	O
class	O
library	B-Library
contains	O
features	O
such	O
as	O
:	O
</s>
<s>
User	B-Application
interface	I-Application
libraries	O
,	O
which	O
include	O
:	O
</s>
<s>
Javadoc	B-Language
is	O
a	O
comprehensive	O
documentation	O
system	O
,	O
created	O
by	O
Sun	O
Microsystems	O
.	O
</s>
<s>
It	O
provides	O
developers	B-Application
with	O
an	O
organized	O
system	O
for	O
documenting	O
their	O
code	O
.	O
</s>
<s>
Javadoc	B-Language
comments	O
have	O
an	O
extra	O
asterisk	O
at	O
the	O
beginning	O
,	O
i.e.	O
</s>
<s>
the	O
delimiters	B-Algorithm
are	O
/	O
**	O
and	O
*	O
/	O
,	O
whereas	O
the	O
normal	O
multi-line	O
comments	O
in	B-Application
Java	I-Application
are	O
delimited	B-Algorithm
by	O
/	O
*	O
and	O
*	O
/	O
,	O
and	O
single-line	O
comments	O
start	O
with	O
//	O
.	O
</s>
<s>
Oracle	B-Application
Corporation	I-Application
is	O
the	O
current	O
owner	O
of	O
the	O
official	O
implementation	O
of	O
the	O
Java	B-Language
SE	I-Language
platform	I-Language
,	O
following	O
their	O
acquisition	O
of	O
Sun	O
Microsystems	O
on	O
January	O
27	O
,	O
2010	O
.	O
</s>
<s>
This	O
implementation	O
is	O
based	O
on	O
the	O
original	O
implementation	O
of	O
Java	B-Device
by	O
Sun	O
.	O
</s>
<s>
The	O
Oracle	B-Application
implementation	O
is	O
available	O
for	O
Microsoft	B-Application
Windows	I-Application
(	O
still	O
works	O
for	O
XP	O
,	O
while	O
only	O
later	O
versions	O
are	O
currently	O
officially	O
supported	O
)	O
,	O
macOS	B-Application
,	O
Linux	B-Operating_System
,	O
and	O
Solaris	B-Application
.	O
</s>
<s>
Because	O
Java	B-Device
lacks	O
any	O
formal	O
standardization	O
recognized	O
by	O
Ecma	O
International	O
,	O
ISO/IEC	O
,	O
ANSI	O
,	O
or	O
other	O
third-party	O
standards	O
organizations	O
,	O
the	O
Oracle	B-Application
implementation	O
is	O
the	O
de	O
facto	O
standard	O
.	O
</s>
<s>
The	O
Oracle	B-Application
implementation	O
is	O
packaged	O
into	O
two	O
different	O
distributions	O
:	O
The	O
Java	B-Language
Runtime	I-Language
Environment	I-Language
(	O
JRE	O
)	O
which	O
contains	O
the	O
parts	O
of	O
the	O
Java	B-Language
SE	I-Language
platform	I-Language
required	O
to	O
run	O
Java	B-Device
programs	O
and	O
is	O
intended	O
for	O
end	O
users	O
,	O
and	O
the	O
Java	B-Language
Development	I-Language
Kit	I-Language
(	O
JDK	B-Language
)	O
,	O
which	O
is	O
intended	O
for	O
software	B-Application
developers	I-Application
and	O
includes	O
development	O
tools	O
such	O
as	O
the	O
Java	B-Language
compiler	I-Language
,	O
Javadoc	B-Language
,	O
Jar	B-Language
,	O
and	O
a	O
debugger	B-Application
.	O
</s>
<s>
Oracle	B-Application
has	O
also	O
released	O
GraalVM	B-Language
,	O
a	O
high	O
performance	O
Java	B-Device
dynamic	B-Language
compiler	B-Language
and	O
interpreter	B-Application
.	O
</s>
<s>
OpenJDK	B-Language
is	O
another	O
notable	O
Java	B-Language
SE	I-Language
implementation	O
that	O
is	O
licensed	O
under	O
the	O
GNU	B-License
GPL	I-License
.	O
</s>
<s>
The	O
implementation	O
started	O
when	O
Sun	O
began	O
releasing	O
the	O
Java	B-Language
source	I-Language
code	I-Language
under	O
the	O
GPL	B-License
.	O
</s>
<s>
As	O
of	O
Java	B-Language
SE	I-Language
7	O
,	O
OpenJDK	B-Language
is	O
the	O
official	O
Java	B-Device
reference	O
implementation	O
.	O
</s>
<s>
The	O
goal	O
of	O
Java	B-Device
is	O
to	O
make	O
all	O
implementations	O
of	O
Java	B-Device
compatible	O
.	O
</s>
<s>
Historically	O
,	O
Sun	O
's	O
trademark	O
license	O
for	O
usage	O
of	O
the	O
Java	B-Device
brand	O
insists	O
that	O
all	O
implementations	O
be	O
compatible	O
.	O
</s>
<s>
This	O
resulted	O
in	O
a	O
legal	O
dispute	O
with	O
Microsoft	O
after	O
Sun	O
claimed	O
that	O
the	O
Microsoft	O
implementation	O
did	O
not	O
support	O
Java	B-Language
remote	I-Language
method	I-Language
invocation	I-Language
(	O
RMI	O
)	O
or	O
Java	B-Language
Native	I-Language
Interface	I-Language
(	O
JNI	B-Language
)	O
and	O
had	O
added	O
platform-specific	O
features	O
of	O
their	O
own	O
.	O
</s>
<s>
As	O
a	O
result	O
,	O
Microsoft	O
no	O
longer	O
ships	O
Java	B-Device
with	O
Windows	B-Application
.	O
</s>
<s>
Platform-independent	O
Java	B-Device
is	O
essential	O
to	O
Java	B-Language
EE	I-Language
,	O
and	O
an	O
even	O
more	O
rigorous	O
validation	O
is	O
required	O
to	O
certify	O
an	O
implementation	O
.	O
</s>
<s>
This	O
environment	O
enables	O
portable	O
server-side	B-Application
applications	O
.	O
</s>
<s>
The	O
Java	B-Language
programming	I-Language
language	I-Language
requires	O
the	O
presence	O
of	O
a	O
software	B-Device
platform	I-Device
in	O
order	O
for	O
compiled	B-Language
programs	O
to	O
be	O
executed	O
.	O
</s>
<s>
Oracle	B-Application
supplies	O
the	O
Java	B-Device
platform	I-Device
for	O
use	O
with	O
Java	B-Device
.	O
</s>
<s>
The	O
Android	B-Application
SDK	I-Application
is	O
an	O
alternative	O
software	B-Device
platform	I-Device
,	O
used	O
primarily	O
for	O
developing	O
Android	B-Application
applications	I-Application
with	O
its	O
own	O
GUI	B-Application
system	O
.	O
</s>
<s>
The	O
Java	B-Language
language	I-Language
is	O
a	O
key	O
pillar	O
in	O
Android	B-Application
,	O
an	O
open	B-Application
source	I-Application
mobile	B-Operating_System
operating	I-Operating_System
system	I-Operating_System
.	O
</s>
<s>
Although	O
Android	B-Application
,	O
built	O
on	O
the	O
Linux	B-Operating_System
kernel	I-Operating_System
,	O
is	O
written	O
largely	O
in	O
C	B-Language
,	O
the	O
Android	B-Application
SDK	I-Application
uses	O
the	O
Java	B-Language
language	I-Language
as	O
the	O
basis	O
for	O
Android	B-Application
applications	I-Application
but	O
does	O
not	O
use	O
any	O
of	O
its	O
standard	O
GUI	B-Application
,	O
SE	O
,	O
ME	O
or	O
other	O
established	O
Java	B-Device
standards	O
.	O
</s>
<s>
The	O
bytecode	B-Language
language	O
supported	O
by	O
the	O
Android	B-Application
SDK	I-Application
is	O
incompatible	O
with	O
Java	B-Language
bytecode	I-Language
and	O
runs	O
on	O
its	O
own	O
virtual	B-Architecture
machine	I-Architecture
,	O
optimized	O
for	O
low-memory	O
devices	O
such	O
as	O
smartphones	B-Application
and	O
tablet	B-Device
computers	I-Device
.	O
</s>
<s>
Depending	O
on	O
the	O
Android	B-Application
version	O
,	O
the	O
bytecode	B-Language
is	O
either	O
interpreted	B-Application
by	O
the	O
Dalvik	B-Application
virtual	I-Application
machine	I-Application
or	O
compiled	B-Language
into	O
native	B-Language
code	I-Language
by	O
the	O
Android	B-Application
Runtime	I-Application
.	O
</s>
<s>
Android	B-Application
does	O
not	O
provide	O
the	O
full	O
Java	B-Language
SE	I-Language
standard	B-Library
library	I-Library
,	O
although	O
the	O
Android	B-Application
SDK	I-Application
does	O
include	O
an	O
independent	O
implementation	O
of	O
a	O
large	O
subset	O
of	O
it	O
.	O
</s>
<s>
It	O
supports	O
Java6	O
and	O
some	O
Java7	O
features	O
,	O
offering	O
an	O
implementation	O
compatible	O
with	O
the	O
standard	B-Library
library	I-Library
(	O
Apache	B-Application
Harmony	I-Application
)	O
.	O
</s>
<s>
The	O
use	O
of	O
Java-related	O
technology	O
in	O
Android	B-Application
led	O
to	O
a	O
legal	O
dispute	O
between	O
Oracle	B-Application
and	O
Google	O
.	O
</s>
<s>
On	O
May	O
7	O
,	O
2012	O
,	O
a	O
San	O
Francisco	O
jury	O
found	O
that	O
if	O
APIs	B-Application
could	O
be	O
copyrighted	O
,	O
then	O
Google	O
had	O
infringed	O
Oracle	B-Application
's	O
copyrights	O
by	O
the	O
use	O
of	O
Java	B-Device
in	O
Android	B-Application
devices	O
.	O
</s>
<s>
District	O
Judge	O
William	O
Alsup	O
ruled	O
on	O
May	O
31	O
,	O
2012	O
,	O
that	O
APIs	B-Application
cannot	O
be	O
copyrighted	O
,	O
but	O
this	O
was	O
reversed	O
by	O
the	O
United	O
States	O
Court	O
of	O
Appeals	O
for	O
the	O
Federal	O
Circuit	O
in	O
May	O
2014	O
.	O
</s>
<s>
On	O
May	O
26	O
,	O
2016	O
,	O
the	O
district	O
court	O
decided	O
in	O
favor	O
of	O
Google	O
,	O
ruling	O
the	O
copyright	O
infringement	O
of	O
the	O
Java	B-Language
API	I-Language
in	O
Android	B-Application
constitutes	O
fair	O
use	O
.	O
</s>
<s>
Google	O
filed	O
a	O
petition	O
for	O
writ	O
of	O
certiorari	O
with	O
the	O
Supreme	O
Court	O
of	O
the	O
United	O
States	O
in	O
January	O
2019	O
to	O
challenge	O
the	O
two	O
rulings	O
that	O
were	O
made	O
by	O
the	O
Appeals	O
Court	O
in	O
Oracle	B-Application
's	O
favor	O
.	O
</s>
<s>
On	O
April	O
5	O
,	O
2021	O
,	O
the	O
Court	O
ruled	O
6-2	O
in	O
Google	O
's	O
favor	O
,	O
that	O
its	O
use	O
of	O
Java	B-Language
APIs	I-Language
should	O
be	O
considered	O
fair	O
use	O
.	O
</s>
<s>
However	O
,	O
the	O
court	O
refused	O
to	O
rule	O
on	O
the	O
copyrightability	O
of	O
APIs	B-Application
,	O
choosing	O
instead	O
to	O
determine	O
their	O
ruling	O
by	O
considering	O
Java	B-Device
's	O
API	B-Application
copyrightable	O
"	O
purely	O
for	O
argument	O
’s	O
sake.	O
"	O
</s>
