<s>
OSGi	B-Application
is	O
an	O
open	O
specification	O
and	O
open	B-License
source	I-License
project	O
under	O
the	B-Application
Eclipse	I-Application
Foundation	I-Application
.	O
</s>
<s>
It	O
is	O
a	O
continuation	O
of	O
the	O
work	O
done	O
by	O
the	O
OSGi	B-Application
Alliance	I-Application
(	O
formerly	O
known	O
as	O
the	O
Open	O
Services	O
Gateway	O
initiative	O
)	O
,	O
which	O
was	O
an	O
open	O
standards	O
organization	O
for	O
computer	B-Application
software	I-Application
founded	O
in	O
March	O
1999	O
.	O
</s>
<s>
The	O
foundation	O
originally	O
specified	O
and	O
maintained	O
the	O
OSGi	B-Application
standard	O
.	O
</s>
<s>
The	O
alliance	O
transferred	O
its	O
work	O
to	O
the	B-Application
Eclipse	I-Application
Foundation	I-Application
at	O
the	O
end	O
of	O
2020	O
.	O
</s>
<s>
The	O
OSGi	B-Application
specification	O
describes	O
a	O
modular	O
system	O
and	O
a	O
service	O
platform	O
for	O
the	O
Java	B-Language
programming	I-Language
language	I-Language
that	O
implements	B-Language
a	O
complete	O
and	O
dynamic	O
component	O
model	O
,	O
something	O
that	O
does	O
not	O
exist	O
in	O
standalone	O
Java	B-Language
or	O
VM	B-Architecture
environments	O
.	O
</s>
<s>
It	O
has	O
a	O
service-oriented	O
architecture	O
based	O
on	O
micro	O
services	O
each	O
implemented	O
as	O
an	O
extended	O
Java	B-Language
class	O
file	O
archive	O
(	O
JAR	B-Language
(	O
file	O
format	O
)	O
)	O
.	O
</s>
<s>
OSGi	B-Application
is	O
built	O
around	O
a	O
service-oriented	O
architecture	O
.	O
</s>
<s>
Applications	B-Application
or	O
components	O
,	O
come	O
in	O
the	O
form	O
of	O
bundles	O
for	O
deployment	B-Application
,	O
can	O
be	O
remotely	O
installed	O
,	O
started	O
,	O
stopped	O
,	O
updated	O
,	O
and	O
uninstalled	O
without	O
requiring	O
a	O
reboot	B-Device
.	O
</s>
<s>
Application	O
life	O
cycle	O
management	O
is	O
implemented	O
via	O
APIs	B-Application
that	O
enable	O
remote	O
downloading	B-Application
of	O
management	O
policies	O
.	O
</s>
<s>
The	O
OSGi	B-Application
specifications	O
have	O
evolved	O
beyond	O
the	O
original	O
focus	O
of	O
service	O
gateways	O
,	O
and	O
are	O
now	O
used	O
in	O
applications	B-Application
ranging	O
from	O
mobile	O
phones	O
to	O
the	O
open-source	B-License
Eclipse	B-Application
IDE	I-Application
.	O
</s>
<s>
Other	O
application	O
areas	O
include	O
automobiles	O
,	O
industrial	O
automation	O
,	O
building	O
automation	O
,	O
PDAs	B-Application
,	O
grid	B-Architecture
computing	I-Architecture
,	O
entertainment	O
,	O
fleet	O
management	O
and	O
application	B-Application
servers	I-Application
.	O
</s>
<s>
In	O
October	O
2020	O
,	O
the	O
OSGi	B-Application
Alliance	I-Application
announced	O
the	O
transition	O
of	O
the	O
standardization	O
effort	O
to	O
the	B-Application
Eclipse	I-Application
Foundation	I-Application
,	O
subsequent	O
to	O
which	O
it	O
would	O
shut	O
down	O
.	O
</s>
<s>
All	O
artifacts	O
have	O
been	O
transferred	O
to	O
the	B-Application
Eclipse	I-Application
Foundation	I-Application
,	O
where	O
an	O
OSGi	B-Application
Working	O
Group	O
"	O
continues	O
to	O
maintain	O
and	O
evolve	O
the	O
specification	O
.	O
</s>
<s>
The	O
OSGi	B-Application
specification	O
is	O
developed	O
by	O
the	O
members	O
in	O
an	O
open	O
process	O
and	O
made	O
available	O
to	O
the	O
public	O
free	O
of	O
charge	O
under	O
the	O
OSGi	B-Application
Specification	O
License	O
.	O
</s>
<s>
The	O
OSGi	B-Application
Alliance	I-Application
has	O
a	O
compliance	O
program	O
that	O
is	O
open	O
to	O
members	O
only	O
.	O
</s>
<s>
As	O
of	O
November	O
2010	O
,	O
there	O
are	O
seven	O
certified	O
OSGi	B-Application
framework	O
implementations	O
.	O
</s>
<s>
A	O
separate	O
page	O
lists	O
both	O
certified	O
and	O
non-certified	O
OSGi	B-Language
Specification	I-Language
Implementations	I-Language
,	O
which	O
include	O
OSGi	B-Application
frameworks	O
and	O
other	O
OSGi	B-Application
specifications	O
.	O
</s>
<s>
OSGi	B-Application
is	O
a	O
Java	B-Language
framework	O
for	O
developing	O
and	O
deploying	O
modular	O
software	O
programs	O
and	O
libraries	O
.	O
</s>
<s>
Each	O
bundle	O
is	O
a	O
tightly	O
coupled	O
,	O
dynamically	O
loadable	O
collection	O
of	O
classes	O
,	O
jars	B-Language
,	O
and	O
configuration	O
files	O
that	O
explicitly	O
declare	O
their	O
external	O
dependencies	O
(	O
if	O
any	O
)	O
.	O
</s>
<s>
BundlesBundles	O
are	O
normal	O
JAR	B-Language
components	O
with	O
extra	O
manifest	O
headers	O
.	O
</s>
<s>
ServicesThe	O
services	O
layer	O
connects	O
bundles	O
in	O
a	O
dynamic	O
way	O
by	O
offering	O
a	O
publish-find-bind	O
model	O
for	O
plain	O
old	O
Java	B-Language
interfaces	I-Language
(	O
POJIs	B-Language
)	O
or	O
plain	B-Language
old	I-Language
Java	I-Language
objects	I-Language
(	O
POJOs	O
)	O
.	O
</s>
<s>
Services	O
RegistryThe	O
application	B-Application
programming	I-Application
interface	I-Application
for	O
management	O
services	O
.	O
</s>
<s>
Life-CycleThe	O
application	B-Application
programming	I-Application
interface	I-Application
for	O
life	O
cycle	O
management	O
(	O
install	O
,	O
start	O
,	O
stop	O
,	O
update	O
,	O
and	O
uninstall	O
)	O
for	O
bundles	O
.	O
</s>
<s>
There	O
is	O
no	O
fixed	O
list	O
of	O
execution	O
environments	O
,	O
since	O
it	O
is	O
subject	O
to	O
change	O
as	O
the	O
Java	B-Language
Community	I-Language
Process	I-Language
creates	O
new	O
versions	O
and	O
editions	O
of	O
Java	B-Language
.	O
</s>
<s>
However	O
,	O
the	O
following	O
set	O
is	O
currently	O
supported	O
by	O
most	O
OSGi	B-Application
implementations	O
:	O
</s>
<s>
A	O
bundle	O
is	O
a	O
group	O
of	O
Java	B-Language
classes	O
and	O
additional	O
resources	O
equipped	O
with	O
a	O
detailed	O
manifest	O
MANIFEST.MF	O
file	O
on	O
all	O
its	O
contents	O
,	O
as	O
well	O
as	O
additional	O
services	O
needed	O
to	O
give	O
the	O
included	O
group	O
of	O
Java	B-Language
classes	O
more	O
sophisticated	O
behaviors	O
,	O
to	O
the	O
extent	O
of	O
deeming	O
the	O
entire	O
aggregate	O
a	O
component	O
.	O
</s>
<s>
Below	O
is	O
an	O
example	O
of	O
a	O
typical	O
MANIFEST.MF	O
file	O
with	O
OSGi	B-Application
Headers	O
:	O
</s>
<s>
Bundle-SymbolicName	O
:	O
The	O
only	O
required	O
header	O
,	O
this	O
entry	O
specifies	O
a	O
unique	O
identifier	O
for	O
a	O
bundle	O
,	O
based	O
on	O
the	O
reverse	B-Protocol
domain	I-Protocol
name	I-Protocol
convention	I-Protocol
(	O
used	O
also	O
by	O
the	O
java	B-Language
packages	I-Language
)	O
.	O
</s>
<s>
Bundle-ManifestVersion	O
:	O
Indicates	O
the	O
OSGi	B-Application
specification	O
to	O
use	O
for	O
reading	O
this	O
bundle	O
.	O
</s>
<s>
Export-Package	O
:	O
Expresses	O
which	O
Java	B-Language
packages	I-Language
contained	O
in	O
a	O
bundle	O
will	O
be	O
made	O
available	O
to	O
the	O
outside	O
world	O
.	O
</s>
<s>
Import-Package	O
:	O
'	O
Indicates	O
which	O
Java	B-Language
packages	I-Language
will	O
be	O
required	O
from	O
the	O
outside	O
world	O
to	O
fulfill	O
the	O
dependencies	O
needed	O
in	O
a	O
bundle	O
.	O
</s>
<s>
Bundles	O
rely	O
on	O
the	O
module	O
layer	O
for	O
class	O
loading	O
but	O
add	O
an	O
API	B-Application
to	O
manage	O
the	O
modules	O
in	O
run	O
time	O
.	O
</s>
<s>
RESOLVED	O
All	O
Java	B-Language
classes	O
that	O
the	O
bundle	O
needs	O
are	O
available	O
.	O
</s>
<s>
Below	O
is	O
an	O
example	O
of	O
a	O
typical	O
Java	B-Language
class	O
implementing	O
the	O
BundleActivator	O
interface	O
:	O
</s>
<s>
import	O
org.osgi.framework.BundleActivator	O
;	O
</s>
<s>
import	O
org.osgi.framework.BundleContext	O
;	O
</s>
<s>
The	O
OSGi	B-Application
Alliance	I-Application
has	O
specified	O
many	O
services	O
.	O
</s>
<s>
Services	O
are	O
specified	O
by	O
a	O
Java	B-Language
interface	I-Language
.	O
</s>
<s>
The	O
table	O
below	O
shows	O
a	O
description	O
of	O
OSGi	B-Application
System	O
Services	O
:	O
</s>
<s>
System	O
Services	O
Description	O
Logging	B-Language
The	O
logging	B-Language
of	O
information	O
,	O
warnings	O
,	O
debug	O
information	O
or	O
errors	O
is	O
handled	O
through	O
the	O
Log	O
Service	O
.	O
</s>
<s>
IO	O
Connector	O
The	O
IO	O
Connector	O
Service	O
implements	B-Language
the	O
CDC/CLDC	O
javax.microedition.io	O
package	O
as	O
a	O
service	O
.	O
</s>
<s>
Preferences	O
Offers	O
an	O
alternative	O
,	O
more	O
OSGi-friendly	O
mechanism	O
to	O
using	O
Java	B-Language
's	O
default	O
for	O
storing	O
preferences	O
.	O
</s>
<s>
Deployment	B-Application
Admin	O
Standardizes	O
access	O
to	O
some	O
of	O
the	O
responsibilities	O
of	O
the	O
management	O
agent	O
.	O
</s>
<s>
Application	O
Admin	O
Simplifies	O
the	O
management	O
of	O
an	O
environment	O
with	O
many	O
different	O
types	O
of	O
applications	B-Application
that	O
are	O
simultaneously	O
available	O
.	O
</s>
<s>
The	O
table	O
below	O
shows	O
a	O
description	O
of	O
OSGi	B-Application
Protocol	O
Services	O
:	O
</s>
<s>
Protocol	O
Services	O
Description	O
HTTP	B-Protocol
Service	O
Allows	O
information	O
to	O
be	O
sent	O
and	O
received	O
from	O
OSGi	B-Application
using	O
HTTP	B-Protocol
.	I-Protocol
</s>
<s>
UPnP	B-Application
Device	O
Service	O
Specifies	O
how	O
OSGi	B-Application
bundles	O
can	O
be	O
developed	O
to	O
interoperate	O
with	O
Universal	B-Application
Plug	I-Application
and	I-Application
Play	I-Application
(	O
UPnP	B-Application
)	O
devices	O
.	O
</s>
<s>
DMT	O
Admin	O
Defines	O
an	O
API	B-Application
for	O
managing	O
a	O
device	O
using	O
concepts	O
from	O
the	O
Open	O
Mobile	O
Alliance	O
(	O
OMA	O
)	O
device	O
management	O
specifications	O
.	O
</s>
<s>
The	O
table	O
below	O
shows	O
a	O
description	O
of	O
OSGi	B-Application
Miscellaneous	O
Services	O
:	O
</s>
<s>
XML	O
Parser	O
The	O
XML	O
Parser	O
service	O
allows	O
a	O
bundle	O
to	O
locate	O
a	O
parser	O
with	O
desired	O
properties	O
and	O
compatibility	O
with	O
JAXP	B-Language
.	O
</s>
<s>
Measurement	O
and	O
State	O
The	O
Measurement	O
and	O
State	O
service	O
allows	O
and	O
simplifies	O
the	O
correct	O
handling	O
of	O
measurements	O
in	O
an	O
OSGi	B-Application
service	O
platform	O
.	O
</s>
<s>
The	O
OSGi	B-Application
Alliance	I-Application
was	O
founded	O
by	O
Ericsson	O
,	O
IBM	O
,	O
Motorola	O
,	O
Sun	O
Microsystems	O
and	O
others	O
in	O
March	O
1999	O
.	O
</s>
<s>
OSGi	B-Application
officers	O
have	O
various	O
roles	O
and	O
responsibilities	O
in	O
supporting	O
the	O
alliance	O
.	O
</s>
<s>
These	O
Expert	O
Groups	O
have	O
produced	O
five	O
major	O
releases	O
of	O
the	O
OSGi	B-Application
specifications	O
(	O
)	O
.	O
</s>
<s>
The	O
Enterprise	O
Expert	O
Group	O
(	O
EEG	O
)	O
is	O
the	O
newest	O
EG	O
and	O
is	O
addressing	O
Enterprise	O
/	O
Server-side	O
applications	B-Application
.	O
</s>
<s>
In	O
October	O
2003	O
,	O
Nokia	O
,	O
Motorola	O
,	O
IBM	O
,	O
ProSyst	B-Language
and	O
other	O
OSGi	B-Application
members	O
formed	O
a	O
Mobile	O
Expert	O
Group	O
(	O
MEG	O
)	O
that	O
will	O
specify	O
a	O
MIDP-based	O
service	O
platform	O
for	O
the	O
next	O
generation	O
of	O
smart	O
mobile	O
phones	O
,	O
addressing	O
some	O
of	O
the	O
needs	O
that	O
CLDC	B-Language
cannot	O
manage	O
-	O
other	O
than	O
CDC	B-Language
.	O
</s>
<s>
MEG	O
became	O
part	O
of	O
OSGi	B-Application
as	O
with	O
R4	O
.	O
</s>
<s>
Fuse	B-Application
ESB	I-Application
-	O
a	O
productized	O
and	O
supported	O
release	O
of	O
ServiceMix	O
4	O
.	O
</s>
<s>
Liferay	B-Language
Dxp	I-Language
-	O
open	B-License
source	I-License
and	O
commercial	O
enterprise	O
Portal	O
platform	O
use	O
OSGi	B-Application
from	O
version	O
7.x	O
.	O
</s>
