<s>
The	O
active	B-Operating_System
object	I-Operating_System
design	O
pattern	O
decouples	O
method	O
execution	O
from	O
method	O
invocation	O
for	O
objects	O
that	O
each	O
reside	O
in	O
their	O
own	O
thread	B-Operating_System
of	O
control	O
.	O
</s>
<s>
The	O
goal	O
is	O
to	O
introduce	O
concurrency	B-Operating_System
,	O
by	O
using	O
asynchronous	B-Operating_System
method	I-Operating_System
invocation	I-Operating_System
and	O
a	O
scheduler	O
for	O
handling	O
requests	O
.	O
</s>
<s>
An	O
interface	O
which	O
defines	O
the	O
method	O
request	O
on	O
an	O
active	B-Operating_System
object	I-Operating_System
.	O
</s>
<s>
The	O
implementation	O
of	O
the	O
active	B-Operating_System
object	I-Operating_System
method	O
.	O
</s>
<s>
An	O
example	O
of	O
active	B-Operating_System
object	I-Operating_System
pattern	O
in	O
Java	B-Language
.	O
</s>
<s>
This	O
class	O
does	O
NOT	O
conform	O
to	O
the	O
active	B-Operating_System
object	I-Operating_System
pattern	O
.	O
</s>
<s>
The	O
class	O
is	O
dangerous	O
in	O
a	O
multithreading	B-Operating_System
scenario	O
because	O
both	O
methods	O
can	O
be	O
called	O
simultaneously	O
,	O
so	O
the	O
value	O
of	O
val	O
(	O
which	O
is	O
not	O
it	O
's	O
updated	O
in	O
multiple	O
steps	O
)	O
could	O
be	O
undefined	O
—	O
a	O
classic	O
race	O
condition	O
.	O
</s>
<s>
To	O
rewrite	O
this	O
class	O
as	O
an	O
active	B-Operating_System
object	I-Operating_System
,	O
you	O
could	O
do	O
the	O
following	O
:	O
</s>
<s>
Another	O
example	O
of	O
active	B-Operating_System
object	I-Operating_System
pattern	O
in	O
Java	B-Language
instead	O
implemented	O
in	O
Java	B-Language
8	O
providing	O
a	O
shorter	O
solution	O
.	O
</s>
