<s>
ESC/Java	B-Application
(	O
and	O
more	O
recently	O
ESC/Java2	B-Application
)	O
,	O
the	O
"	O
Extended	O
Static	O
Checker	O
for	O
Java	B-Language
,	O
"	O
is	O
a	O
programming	B-Application
tool	I-Application
that	O
attempts	O
to	O
find	O
common	O
run-time	B-Library
errors	I-Library
in	O
Java	B-Language
programs	O
at	O
compile	B-Application
time	I-Application
.	O
</s>
<s>
The	O
underlying	O
approach	O
used	O
in	O
ESC/Java	B-Application
is	O
referred	O
to	O
as	O
extended	B-Application
static	I-Application
checking	I-Application
,	O
which	O
is	O
a	O
collective	O
name	O
referring	O
to	O
a	O
range	O
of	O
techniques	O
for	O
statically	O
checking	O
the	O
correctness	O
of	O
various	O
program	O
constraints	O
.	O
</s>
<s>
For	O
example	O
,	O
that	O
an	O
integer	O
variable	O
is	O
greater-than-zero	O
,	O
or	O
lies	O
between	O
the	O
bounds	B-Data_Structure
of	I-Data_Structure
an	I-Data_Structure
array	I-Data_Structure
.	O
</s>
<s>
This	O
technique	O
was	O
pioneered	O
in	O
ESC/Java	B-Application
(	O
and	O
its	O
predecessor	O
,	O
ESC/Modula	O
-3	O
)	O
and	O
can	O
be	O
thought	O
of	O
as	O
an	O
extended	O
form	O
of	O
type	O
checking	O
.	O
</s>
<s>
Extended	B-Application
static	I-Application
checking	I-Application
usually	O
involves	O
the	O
use	O
of	O
an	O
automated	B-Application
theorem	I-Application
prover	I-Application
and	O
,	O
in	O
ESC/Java	B-Application
,	O
the	O
Simplify	O
theorem	B-Application
prover	I-Application
was	O
used	O
.	O
</s>
<s>
ESC/Java	B-Application
is	O
neither	O
sound	O
nor	O
complete	O
.	O
</s>
<s>
However	O
,	O
it	O
does	O
mean	O
that	O
:	O
firstly	O
,	O
there	O
are	O
programs	O
that	O
ESC/Java	B-Application
will	O
erroneously	O
consider	O
to	O
be	O
incorrect	O
(	O
known	O
as	O
false-positives	O
)	O
;	O
secondly	O
,	O
there	O
are	O
incorrect	O
programs	O
it	O
will	O
consider	O
to	O
be	O
correct	O
(	O
known	O
as	O
false-negatives	O
)	O
.	O
</s>
<s>
Examples	O
in	O
the	O
latter	O
category	O
include	O
errors	O
arising	O
from	O
modular	O
arithmetic	O
and/or	O
multithreading	B-Operating_System
.	O
</s>
<s>
ESC/Java	B-Application
was	O
originally	O
developed	O
at	O
the	O
Compaq	O
Systems	O
Research	O
Center	O
(	O
SRC	O
)	O
.	O
</s>
<s>
In	O
2002	O
,	O
SRC	O
released	O
the	O
source	O
code	O
for	O
ESC/Java	B-Application
and	O
related	O
tools	O
.	O
</s>
<s>
Recent	O
versions	O
of	O
ESC/Java	B-Application
are	O
based	O
around	O
the	O
Java	B-Language
Modeling	I-Language
Language	I-Language
(	O
JML	B-Language
)	O
.	O
</s>
<s>
The	O
University	O
of	O
Nijmegen	O
's	O
Security	O
of	O
Systems	O
group	O
released	O
alpha	O
versions	O
of	O
ESC/Java2	B-Application
,	O
an	O
extended	O
version	O
of	O
ESC/Java	B-Application
that	O
processes	O
the	O
JML	B-Language
specification	O
language	O
through	O
2004	O
.	O
</s>
<s>
From	O
2004	O
to	O
2009	O
,	O
ESC/Java2	B-Application
development	O
was	O
managed	O
by	O
the	O
KindSoftware	O
Research	O
Group	O
at	O
University	O
College	O
Dublin	O
,	O
which	O
in	O
2009	O
moved	O
to	O
the	O
IT	O
University	O
of	O
Copenhagen	O
,	O
and	O
in	O
2012	O
to	O
the	O
Technical	O
University	O
of	O
Denmark	O
.	O
</s>
<s>
Over	O
the	O
years	O
,	O
ESC/Java2	B-Application
has	O
gained	O
many	O
new	O
features	O
including	O
the	O
ability	O
to	O
reason	O
with	O
multiple	O
theorem	O
provers	O
and	O
integration	O
with	O
Eclipse	B-Application
.	O
</s>
<s>
,	O
the	O
successor	O
of	O
ESC/Java2	B-Application
,	O
is	O
available	O
for	O
Java	B-Language
1.8	O
.	O
</s>
