<s>
Apache	B-Language
ObJectRelationalBridge	I-Language
(	O
OJB	B-Language
)	O
is	O
an	O
Object/Relational	B-General_Concept
mapping	I-General_Concept
tool	O
that	O
allows	O
transparent	O
persistence	B-Application
for	O
Java	B-Language
Objects	O
against	O
relational	B-Application
databases	I-Application
.	O
</s>
<s>
As	O
of	O
January	O
16	O
,	O
2011	O
Apache	B-Language
ObJectRelationalBridge	I-Language
has	O
been	O
retired	O
.	O
</s>
<s>
OJB	B-Language
is	O
an	O
open	B-Application
source	I-Application
project	O
.	O
</s>
<s>
It	O
is	O
lightweight	O
and	O
easy	O
to	O
use	O
,	O
requiring	O
simply	O
configure	O
two	O
files	O
to	O
implement	O
a	O
persistence	B-Application
layer	O
.	O
</s>
<s>
It	O
allows	O
the	O
use	O
of	O
different	O
patterns	O
of	O
persistence	B-Application
:	O
owner	O
(	O
PersistenceBroker	O
API	B-General_Concept
)	O
,	O
JDO	B-Language
and	O
Object	B-Application
Data	I-Application
Management	I-Application
Group	I-Application
(	O
ODMG	B-Application
)	O
.	O
</s>
<s>
OJB	B-Language
uses	O
an	O
XML	B-Protocol
based	O
Object/Relational	B-General_Concept
mapping	I-General_Concept
.	O
</s>
<s>
The	O
mapping	O
resides	O
in	O
a	O
dynamic	O
MetaData	O
layer	O
,	O
which	O
can	O
be	O
manipulated	O
at	O
runtime	O
through	O
a	O
simple	O
Meta-Object-Protocol	O
(	O
MOP	O
)	O
to	O
change	O
the	O
behaviour	O
of	O
the	O
persistence	B-Application
kernel	O
.	O
</s>
