<s>
.properties	B-Protocol
is	O
a	O
file	O
extension	O
for	O
files	B-Operating_System
mainly	O
used	O
in	O
Java-related	O
technologies	O
to	O
store	O
the	O
configurable	O
parameters	O
of	O
an	O
application	B-Application
.	O
</s>
<s>
They	O
can	O
also	O
be	O
used	O
for	O
storing	O
strings	O
for	O
Internationalization	B-General_Concept
and	I-General_Concept
localization	I-General_Concept
;	O
these	O
are	O
known	O
as	O
Property	O
Resource	B-Language
Bundles	I-Language
.	O
</s>
<s>
Unlike	O
many	O
popular	O
file	O
formats	O
,	O
there	O
is	O
no	O
RFC	O
for	O
.properties	B-Protocol
files	B-Operating_System
and	O
specification	O
documents	O
are	O
not	O
always	O
clear	O
,	O
most	O
likely	O
due	O
to	O
the	O
simplicity	O
of	O
the	O
format	O
.	O
</s>
<s>
Each	O
line	O
in	O
a	O
.properties	B-Protocol
file	O
normally	O
stores	O
a	O
single	O
property	O
.	O
</s>
<s>
Comment	O
lines	O
in	O
.properties	B-Protocol
files	B-Operating_System
are	O
denoted	O
by	O
the	O
number	O
sign	O
( #	O
)	O
or	O
the	O
exclamation	O
mark	O
(	O
!	O
)	O
</s>
<s>
An	O
example	O
of	O
a	O
properties	B-Protocol
file	I-Protocol
is	O
provided	O
below	O
.	O
</s>
<s>
Before	O
Java	B-Language
9	O
,	O
the	O
encoding	O
of	O
a	O
.properties	B-Protocol
file	O
is	O
ISO-8859-1	O
,	O
also	O
known	O
as	O
Latin-1	O
.	O
</s>
<s>
This	O
allows	O
for	O
using	O
.properties	B-Protocol
files	B-Operating_System
as	O
resource	B-Language
bundles	I-Language
for	O
localization	B-General_Concept
.	O
</s>
<s>
A	O
non-Latin-1	O
text	O
file	O
can	O
be	O
converted	O
to	O
a	O
correct	O
.properties	B-Protocol
file	O
by	O
using	O
the	O
native2ascii	O
tool	O
that	O
is	O
shipped	O
with	O
the	O
JDK	B-Language
or	O
by	O
using	O
a	O
tool	O
,	O
such	O
as	O
po2prop	O
,	O
that	O
manages	O
the	O
transformation	O
from	O
a	O
bilingual	O
localization	B-General_Concept
format	O
into	O
.properties	B-Protocol
escaping	O
.	O
</s>
<s>
An	O
alternative	O
to	O
using	O
unicode	O
escape	O
characters	O
for	O
non-Latin-1	O
character	O
in	O
ISO	O
8859-1	O
character	O
encoded	O
Java	B-Language
*	O
.properties	B-Protocol
files	B-Operating_System
is	O
to	O
use	O
the	O
JDK	B-Language
's	O
XML	B-Protocol
Properties	B-Protocol
file	I-Protocol
format	O
which	O
by	O
default	O
is	O
UTF-8	O
encoded	O
,	O
introduced	O
starting	O
with	O
Java	B-Language
1.5	O
.	O
</s>
<s>
In	O
Java	B-Language
9	O
and	O
newer	O
,	O
the	O
default	O
encoding	O
specifically	O
for	O
property	O
resource	B-Language
bundles	I-Language
is	O
UTF-8	O
,	O
and	O
if	O
an	O
invalid	O
UTF-8	O
byte	O
sequence	O
is	O
encountered	O
it	O
falls	O
back	O
to	O
ISO-8859-1	O
.	O
</s>
<s>
Editing	O
.properties	B-Protocol
files	B-Operating_System
is	O
done	O
using	O
any	O
text	B-Application
editor	I-Application
such	O
as	O
those	O
typically	O
installed	O
on	O
various	O
Operating	B-General_Concept
Systems	I-General_Concept
including	O
Notepad	B-Application
on	O
Windows	O
or	O
Emacs	B-Application
,	O
Vim	B-Application
,	O
etc	O
.	O
</s>
<s>
Third-party	O
tools	O
are	O
also	O
available	O
with	O
additional	O
functionality	O
specific	O
to	O
editing	O
.properties	B-Protocol
files	B-Operating_System
such	O
as	O
:	O
</s>
<s>
Apache	B-Operating_System
Flex	I-Operating_System
uses	O
.properties	B-Protocol
files	B-Operating_System
as	O
well	O
,	O
but	O
here	O
they	O
are	O
UTF-8	O
encoded	O
.	O
</s>
<s>
Perl	B-Language
CPAN	B-Language
contains	O
Config::Properties	O
to	O
interface	O
to	O
a	O
.properties	B-Protocol
file	O
.	O
</s>
<s>
There	O
are	O
many	O
Node.js	O
(	O
JavaScript/TypeScript	O
)	O
options	O
available	O
on	O
Npm	B-Language
's	O
package	O
manager	O
.	O
</s>
<s>
PHP	B-Application
also	O
has	O
many	O
package	O
options	O
available	O
.	O
</s>
