<s>
A	O
Java	B-Language
compiler	I-Language
is	O
a	O
compiler	B-Language
for	O
the	O
programming	O
language	O
Java	B-Language
.	O
</s>
<s>
The	O
most	O
common	O
form	O
of	O
output	O
from	O
a	O
Java	B-Language
compiler	I-Language
is	O
Java	B-Language
class	I-Language
files	I-Language
containing	O
platform-neutral	O
Java	B-Language
bytecode	I-Language
,	O
but	O
there	O
are	O
also	O
compilers	B-Language
that	O
output	O
optimized	O
native	B-Language
machine	I-Language
code	I-Language
for	O
a	O
particular	O
hardware/operating	O
system	O
combination	O
,	O
most	O
notably	O
the	O
now	O
discontinued	O
GNU	B-Language
Compiler	I-Language
for	I-Language
Java	I-Language
.	O
</s>
<s>
Most	O
Java-to-bytecode	O
compilers	B-Language
do	O
virtually	O
no	O
optimization	O
,	O
leaving	O
this	O
until	O
run	B-Library
time	I-Library
to	O
be	O
done	O
by	O
the	O
Java	B-Language
virtual	I-Language
machine	I-Language
(	O
JVM	B-Language
)	O
.	O
</s>
<s>
The	O
JVM	B-Language
loads	O
the	O
class	B-Language
files	I-Language
and	O
either	O
interprets	B-Application
the	O
bytecode	O
or	O
just-in-time	O
compiles	B-Language
it	O
to	O
machine	B-Language
code	I-Language
and	O
then	O
possibly	O
optimizes	O
it	O
using	O
dynamic	B-Application
compilation	I-Application
.	O
</s>
<s>
A	O
standard	O
on	O
how	O
to	O
interact	O
with	O
Java	B-Language
compilers	I-Language
programmatically	O
was	O
specified	O
in	O
JSR	B-Language
199	I-Language
.	O
</s>
