<s>
HotSpot	B-Language
,	O
released	O
as	O
Java	O
HotSpot	B-Language
Performance	O
Engine	O
,	O
is	O
a	O
Java	B-Language
virtual	I-Language
machine	I-Language
for	O
desktop	B-Device
and	O
server	B-Application
computers	I-Application
,	O
developed	O
by	O
Sun	O
Microsystems	O
and	O
now	O
maintained	O
and	O
distributed	O
by	O
Oracle	B-Application
Corporation	I-Application
.	O
</s>
<s>
The	O
Java	O
HotSpot	B-Language
Performance	O
Engine	O
was	O
released	O
on	O
April	O
27	O
,	O
1999	O
,	O
built	O
on	O
technologies	O
from	O
an	O
implementation	O
of	O
the	O
programming	O
language	O
Smalltalk	B-Application
named	O
Strongtalk	B-Language
,	O
originally	O
developed	O
by	O
Longview	B-Language
Technologies	I-Language
,	O
which	O
traded	O
as	O
Animorphic	O
.	O
</s>
<s>
The	O
Longview	O
virtual	O
machine	O
was	O
based	O
on	O
the	O
Self	B-Operating_System
virtual	O
machine	O
,	O
with	O
an	O
interpreter	B-Application
replacing	O
the	O
fast-and-dumb	O
first	O
compiler	O
.	O
</s>
<s>
When	O
Sun	O
cancelled	O
the	O
Self	B-Operating_System
project	O
,	O
two	O
key	O
people	O
,	O
Urs	O
Hölzle	O
and	O
Lars	O
Bak	O
left	O
Sun	O
to	O
start	O
Longview	O
.	O
</s>
<s>
Shortly	O
after	O
acquiring	O
Animorphic	O
,	O
Sun	O
decided	O
to	O
write	O
a	O
new	O
just-in-time	O
(	O
JIT	O
)	O
compiler	O
for	O
the	O
Java	B-Language
virtual	I-Language
machine	I-Language
.	O
</s>
<s>
This	O
new	O
compiler	O
would	O
give	O
rise	O
to	O
the	O
name	O
HotSpot	B-Language
,	O
derived	O
from	O
the	O
software	O
's	O
behavior	O
:	O
as	O
it	O
runs	O
Java	B-Language
bytecode	I-Language
,	O
as	O
with	O
the	O
Self	B-Operating_System
VM	O
,	O
HotSpot	B-Language
continually	O
analyzes	O
the	O
program	O
's	O
performance	O
for	O
hot	O
spots	O
which	O
are	O
executed	O
often	O
or	O
repeatedly	O
.	O
</s>
<s>
In	O
one	O
report	O
,	O
the	O
JVM	B-Language
beat	O
some	O
C++	B-Language
or	O
C	B-Language
code	O
in	O
some	O
benchmarks	O
.	O
</s>
<s>
Initially	O
available	O
as	O
an	O
add-on	O
for	O
Java	O
1.2	O
,	O
HotSpot	B-Language
became	O
the	O
default	O
Sun	O
JVM	B-Language
in	O
Java	O
1.3	O
.	O
</s>
<s>
JRE	O
(	O
originally	O
from	O
Sun	O
,	O
now	O
from	O
Oracle	B-Application
)	O
features	O
two	O
virtual	O
machines	O
,	O
one	O
called	O
Client	O
and	O
the	O
other	O
Server	B-Application
.	O
</s>
<s>
The	O
Server	B-Application
version	O
loads	O
more	O
slowly	O
,	O
putting	O
more	O
effort	O
into	O
producing	O
highly	O
optimized	O
JIT	O
compilations	O
to	O
yield	O
higher	O
performance	O
.	O
</s>
<s>
Tiered	O
compiling	O
,	O
an	O
option	O
introduced	O
in	O
Java	O
7	O
,	O
uses	O
both	O
the	O
client	O
and	O
server	B-Application
compilers	O
in	O
tandem	O
to	O
provide	O
faster	O
startup	O
time	O
than	O
the	O
server	B-Application
compiler	O
,	O
but	O
similar	O
or	O
better	O
peak	O
performance	O
.	O
</s>
<s>
Starting	O
in	O
Java	O
8	O
,	O
tiered	O
compilation	O
is	O
the	O
default	O
for	O
the	O
server	B-Application
VM	O
.	O
</s>
<s>
HotSpot	B-Language
is	O
written	O
in	O
C++	B-Language
and	O
Assembly	B-Language
.	O
</s>
<s>
Hotspot	B-Language
provides	O
:	O
</s>
<s>
HotSpot	B-Language
supports	O
many	O
command-line	O
arguments	O
for	O
options	O
of	O
the	O
virtual	O
machine	O
execution	O
.	O
</s>
<s>
Some	O
are	O
standard	O
and	O
must	O
be	O
found	O
in	O
any	O
conforming	O
Java	B-Language
virtual	I-Language
machine	I-Language
;	O
others	O
are	O
specific	O
to	O
HotSpot	B-Language
and	O
may	O
not	O
be	O
found	O
in	O
other	O
JVMs	B-Language
(	O
options	O
that	O
begin	O
with	O
-X	O
or	O
-XX	O
are	O
non-standard	O
)	O
.	O
</s>
<s>
On	O
13	O
November	O
2006	O
,	O
the	O
HotSpot	B-Language
JVM	B-Language
and	O
the	O
Java	B-Language
Development	I-Language
Kit	I-Language
(	O
JDK	B-Language
)	O
were	O
licensed	O
under	O
the	O
GNU	B-License
General	I-License
Public	I-License
License	I-License
(	O
GPL	B-License
)	O
version	O
2	O
.	O
</s>
<s>
As	O
with	O
the	O
entire	O
Java	B-Language
Development	I-Language
Kit	I-Language
(	O
JDK	B-Language
)	O
,	O
HotSpot	B-Language
is	O
supported	O
by	O
Oracle	B-Application
Corporation	I-Application
on	O
Windows	B-Application
,	O
Linux	B-Application
,	O
and	O
macOS	B-Application
.	O
</s>
<s>
Supported	O
instruction	B-General_Concept
set	I-General_Concept
architectures	I-General_Concept
(	O
ISAs	O
)	O
are	O
x86-64	B-Device
and	O
AArch64	B-Architecture
.	O
</s>
<s>
Since	O
JDK	B-Language
15	O
,	O
Solaris	B-Application
and	O
SPARC	B-Architecture
are	O
no	O
longer	O
supported	O
.	O
</s>
<s>
Ports	O
are	O
also	O
available	O
by	O
third	O
parties	O
for	O
various	O
other	O
Unix	B-Application
operating	I-Application
systems	I-Application
.	O
</s>
<s>
Several	O
different	O
hardware	O
architectures	O
are	O
supported	O
,	O
including	O
x86	B-Operating_System
,	O
PowerPC	B-Architecture
,	O
and	O
SPARC	B-Architecture
(	O
Solaris	B-Application
only	O
)	O
.	O
</s>
<s>
Porting	O
HotSpot	B-Language
is	O
difficult	O
,	O
as	O
much	O
of	O
it	O
is	O
almost	O
extensively	O
written	O
in	O
assembly	B-Language
language	I-Language
,	O
though	O
several	O
sections	O
of	O
it	O
are	O
also	O
written	O
in	O
purely	O
standards	B-Language
conformant	I-Language
ISO	I-Language
C++	I-Language
.	O
</s>
<s>
To	O
remedy	O
this	O
,	O
the	O
IcedTea	B-Language
project	O
has	O
developed	O
a	O
generic	O
port	O
of	O
the	O
HotSpot	B-Language
interpreter	B-Application
called	O
zero-assembler	O
Hotspot	B-Language
(	O
or	O
zero	O
)	O
,	O
with	O
almost	O
no	O
assembly	B-Language
code	I-Language
.	O
</s>
<s>
This	O
port	O
is	O
intended	O
for	O
easy	O
adaptation	O
of	O
the	O
interpreter	B-Application
component	O
of	O
HotSpot	B-Language
to	O
any	O
Linux	B-Application
processor	O
architecture	O
.	O
</s>
<s>
The	O
code	O
of	O
zero-assembler	O
Hotspot	B-Language
is	O
used	O
for	O
all	O
the	O
non-x86	O
architecture	O
ports	O
of	O
HotSpot	B-Language
(	O
PowerPC	B-Architecture
,	O
Itanium	B-General_Concept
(	O
IA-64	B-General_Concept
)	O
,	O
S390	B-Device
and	O
ARM	B-Architecture
)	O
since	O
version	O
1.6	O
.	O
</s>
