<s>
In	O
computer	B-General_Concept
programming	I-General_Concept
,	O
glue	B-General_Concept
code	I-General_Concept
is	O
executable	O
code	O
(	O
often	O
source	O
code	O
)	O
that	O
serves	O
solely	O
to	O
"	O
adapt	O
"	O
different	O
parts	O
of	O
code	O
that	O
would	O
otherwise	O
be	O
incompatible	B-Application
.	O
</s>
<s>
Glue	B-General_Concept
code	I-General_Concept
does	O
not	O
contribute	O
any	O
functionality	O
towards	O
meeting	O
program	O
requirements	O
.	O
</s>
<s>
Instead	O
,	O
it	O
often	O
appears	O
in	O
code	O
that	O
lets	O
existing	O
libraries	B-Library
or	O
programs	O
interoperate	O
,	O
as	O
in	O
language	B-Application
bindings	I-Application
or	O
foreign	B-Application
function	I-Application
interfaces	I-Application
such	O
as	O
the	O
Java	B-Language
Native	I-Language
Interface	I-Language
,	O
when	O
mapping	O
objects	O
to	O
a	O
database	O
using	O
object-relational	B-General_Concept
mapping	I-General_Concept
,	O
or	O
when	O
integrating	O
two	O
or	O
more	O
commercial	O
off-the-shelf	O
programs	O
.	O
</s>
<s>
Glue	B-General_Concept
code	I-General_Concept
may	O
be	O
written	O
in	O
the	O
same	O
language	O
as	O
the	O
code	O
it	O
is	O
gluing	O
together	O
,	O
or	O
in	O
a	O
separate	O
glue	O
language	O
.	O
</s>
<s>
Glue	B-General_Concept
code	I-General_Concept
is	O
very	O
efficient	O
in	O
rapid	B-Device
prototyping	I-Device
environments	O
,	O
where	O
several	O
components	O
are	O
quickly	O
put	O
together	O
into	O
a	O
single	O
language	O
or	O
framework	O
.	O
</s>
<s>
it	O
is	O
unaware	O
of	O
its	O
relations	O
and	O
is	O
only	O
connected	O
to	O
another	O
component	O
through	O
glue	B-General_Concept
code	I-General_Concept
)	O
,	O
the	O
behavior	O
of	O
a	O
component	O
and	O
its	O
interactions	O
can	O
change	O
during	O
the	O
execution	O
of	O
the	O
script	O
.	O
</s>
<s>
In	O
addition	O
,	O
a	O
different	O
version	O
of	O
one	O
of	O
the	O
components	O
may	O
behave	O
differently	O
,	O
breaking	O
the	O
glue	B-General_Concept
code	I-General_Concept
.	O
</s>
<s>
High-level	O
programming	O
languages	O
can	O
suffer	O
from	O
performance	O
penalties	O
because	O
glue	B-General_Concept
code	I-General_Concept
must	O
run	O
through	O
the	O
language	O
interpreter	O
,	O
even	O
when	O
connecting	O
high-performance	O
subsystems	O
.	O
</s>
<s>
In	O
object-oriented	O
scripting	B-Language
languages	I-Language
,	O
glue	B-General_Concept
code	I-General_Concept
often	O
eliminates	O
the	O
need	O
for	O
class	O
hierarchies	O
and	O
large	O
numbers	O
of	O
classes	O
.	O
</s>
