Java Reference
In-Depth Information
commercial product, with no open source license. This has some—obvious—costs
and also some advantages. Both Nimble and WebSphere Application Server are free
to use for evaluation and development, so you'll only need to buy a license when you
move into production. Because of their commercial nature, both Nimble and Web-
Sphere Application Server come with professional support. Two of the other servers
we discussed, GlassFish and
JB
oss, have the option of paid support with premium
editions. And Karaf, Geronimo, and Virgo have active mailing lists and helpful devel-
opment communities.
13.9
Summary
With so many products to choose from, how on earth do you choose one? It may be
your choice is already made for you because you're working in an Apache shop, or a
JB
oss shop, or a WebSphere shop. The good news is that with so many products sup-
porting enterprise
OSG
i, you've got a good chance of having a platform on which you
can write modular applications, even if the decision about what application server to
use has already been settled.
If you're starting from scratch, there are a few factors to consider. Do you want an
open source license, an open source license with paid support, or a commercial
license? Are you willing to get under the hood and bolt bits together, or do you want
something that works out of the box? Do you want a super-light
OSG
i platform, or a
full-featured server? Do you need the whole enterprise
OSG
i programming model, or
will web applications or dependency injection do? Ultimately, how much server do
you need? Table 13.2 shows how the various stacks compare to each other in terms of
cost and scale.
Table 13.2
Feature comparison of enterprise OSGi servers
Apache
Geronimo
IBM
WebSphere
Paremus
Nimble
Server
Apache Karaf
Eclipse Virgo
GlassFish
JBoss
Vendor
Apache
Software
Foundation
Apache
Software
Foundation
IBM
Eclipse
Oracle
Red Hat
Paremus
License
Apache
license
Apache
license
Proprietary
license
(free
restricted
license for
developers)
Eclipse Pub-
lic License
Dual
license:
Common
Develop-
ment and
Distribution
License
(CDDL) and
GNU Gen-
eral Public
License
(GPL)
GNU Lesser
General
Public
License
(LGPL)
Proprietary
license
(Nimble
only avail-
able with a
free
restricted
license for
developers)
