<s>
Gerrit	B-Language
(	O
)	O
is	O
a	O
free	O
,	O
web-based	B-Application
team	O
code	O
collaboration	O
tool	O
.	O
</s>
<s>
Software	O
developers	O
in	O
a	O
team	O
can	O
review	O
each	O
other	O
's	O
modifications	O
on	O
their	O
source	O
code	O
using	O
a	O
Web	B-Application
browser	I-Application
and	O
approve	O
or	O
reject	O
those	O
changes	O
.	O
</s>
<s>
It	O
integrates	O
closely	O
with	O
Git	B-Application
,	O
a	O
distributed	B-Protocol
version	I-Protocol
control	I-Protocol
system	I-Protocol
.	O
</s>
<s>
Gerrit	B-Language
is	O
a	O
fork	B-Application
of	O
Rietveld	B-Language
,	O
a	O
code	O
review	O
tool	O
for	O
Subversion	B-Application
.	O
</s>
<s>
Both	O
are	O
namesakes	O
of	O
Dutch	O
designer	O
Gerrit	B-Language
Rietveld	B-Language
.	O
</s>
<s>
Originally	O
written	O
in	O
Python	B-Language
like	O
Rietveld	B-Language
,	O
it	O
is	O
now	O
written	O
in	O
Java	B-Language
(	O
Java	B-Language
EE	I-Language
Servlet	B-Application
)	O
with	O
SQL	B-Language
since	O
version	O
2	O
and	O
a	O
custom-made	O
Git-based	O
database	O
(	O
NoteDb	O
)	O
since	O
version	O
3	O
.	O
</s>
<s>
In	O
versions	O
2.0	O
–	O
2.16	O
Gerrit	B-Language
used	O
Google	B-Language
Web	I-Language
Toolkit	I-Language
for	O
its	O
browser-based	B-Application
front-end	O
.	O
</s>
<s>
After	O
being	O
developed	O
and	O
used	O
in	O
parallel	O
with	O
GWT	B-Language
for	O
versions	O
2.14	O
–	O
2.16	O
,	O
a	O
new	O
Polymer	B-Language
web	O
UI	O
replaced	O
the	O
GWT	B-Language
UI	O
in	O
version	O
3.0	O
.	O
</s>
