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OSGI exams
At 3:19 AM on Aug 3, 2007, Henryk Konsek wrote:
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This thread was created in order to coordinate the process of creation of the new OSGI-related exams.
Toni, personally I'm not familiar with the OSGI, so I cannot propose the exam objectives nor verify the essential content of the latter however I'll help you (and any other volunteers) with fitting the objectives into an appropriate form. Feel free to ask me here or by e-mail.
Toni, you mentioned in the mail that you want to split the topic into a few exams including the base one. I suggest then to start with the 'OSGI Basic' exam objectives. Could you create and submit a draft here?
Any others volunteers?
Best regards.
14 replies so far (
Post your own)
Re: OSGI exams
hi,this is Toni Menzel, a software developer and student from hannover, germany.
Henryk just introduced me a while back pointing JavaBlackBelt to a missing exam about OSGi.
You'll get most more abstract definitions on the officical website (http://osgi.org) but in short they
discribe it as "OSGi technology is the dynamic module system for Java".
Infact, OSGi Core is a dense & concise about 288 pages specification.
It is well known as the vehicle of eclipse (since 3.0) as well as a (somtimes disliked by some people) more
sophisticated and proven JSR 277 (Java Module System - hint: just speaking of the module-layer of osgi)
More companies are considering OSGi as a platform just because more and more framework implementations
are getting stable. To name the most prominent ones:
- http://felix.apache.org
- http://www.eclipse.org/equinox/
- http://www.knopflerfish.org/
- http://concierge.sourceforge.net/
as well as a growing toolchain that makes life a lot easier. Here are some you should
know about if you think of going into osgi:
- http://www.aqute.biz/Code/Bnd
- http://felix.apache.org/site/maven-bundle-plugin-bnd.html
- http://wiki.ops4j.org/confluence/display/ops4j/Pax+Runner
- http://www.ops4j.org/projects/pax/construct/
So what can we do at JavaBlackBelt.com for osgi and the growing customerbase?
Well, first we should split knowledge (aka tests) into layers as defined by the specification:
1. Module-Layer
2. Security Layer
3. Life Cycle Layer
4. Service Layer
This would contain knowlegde drawn just from the osgi specification.
So for the Module Layer a very simple but essential question could be:
1.) "If a bundle has exports package org.foo.api it must contain that package"
Yes / No
(No, it doesn't have to. That would be known as dependency substitution. Here the bundle must import AND export the bundle)
2.) "Which MANIFEST Headers is/are mandatory"
* Bundle-Version
* Bundle-SymbolicName
* Bundle-Name
(its just the Bundle-SymbolicName)
In the end we then mix those questions into a first "Basic OSGi" Exam which scope is just all about the R4.1 (most current release) specification.
The level should be rather easy because it contains essential knowledge you should know about.
I will try to craft a first full fletched exam (made of 20 Questions) with the scope described about and
post it to this thread. (or is another suggest way to initially craft a exam?)
For me, a starting point are some mailinglists where some questions show up pretty often,
so its taken from the real world and nothing too academic.
--> http://www2.osgi.org/mailman/listinfo/osgi-dev
Please contribute & ask what you think about that, guys!
To the osgi-geeks: post exam-questions !!!
have a nice day, Toni
--
Toni Menzel
tonimenzel at gmx dot de
tonitcom.blogspot.com
Re: OSGI exams
Here are some more abstract goals for the "Basic OSGi Exam":- Learn that ClassLoaders are involved heavily, so its very different from what most J2EE developers think of.
But know that osgi's Module-Layer pulls down the complexity of this power jvm capability. Anyway, you must learn some things about it.
- Learn that osgi has a package plus version dependency identifier. So running different versions of the same package is possible.
- Learn that osgi is a specification originally designed for embedded and constraint devices. Proven (its been around a while!) dynamic behavior and resource efficient principles
as well as a tight and clear specification makes osgi eligable for the enterprise, too.
I'll post more points later.
Toni
Re: OSGI exams
- Learn that a Bundle is usually just a jar file with extra meta-data, essentially inside META-INF/MANIFEST.MF- Learn that to be a mininmum bundle you need some Headers in your MANIFEST (mandatory meta data)
- Learn that the Bundle is the unit of modularization
- a bundle usually contains java bytecode, native code and/or libraries, resources. Thus functionality is not tied to java
- Bundles collaborate through the Module Layer (package sharing), Service Layer or one of the more advanced built-on-top-of-service-layer bundles like eclipse service registry, apache felix ipojo or pring-osgi
Re: OSGI exams
Hi Toni, thank you for this introduction.You may like to write a first draft of the Osgi - basic exam objectives on a wiki page and refer it in this forum.
When it's done, we can post a news on JBB.com.
Don't hesitate to review the "how to write good objectives" page:
http://www.javablackbelt.com/WikiPage.wwa?action=view&page=AboutHowToWriteObjectives
I also suggest that you have a look at existing exam's objectives.
You'll also need to provide sub-categories with an amount of asked question for each.
Thank you for contributing !
John.
Re: OSGI exams
One more thing, Toni:Imagine what a developer who knows nothing about Osgi, should learn about it in 3 days -> and you get an idea of the objectives of a basic exam.
Don't make them too abstract (bound to the specification). I guess it's possible to make concrete things with Osgi.
Just an advice.
John.
Re: OSGI exams
Hi John,thanks for your advice!
I initially started with the wiki here: http://nutritioussoftware.org/space/javablackbelt/osgiBasicExam
Re: OSGI exams
Hi John,the main objectives for the exam are pretty much done now.
Perhaps you or your fellow can have a look at it: http://nutritioussoftware.org/space/javablackbelt/osgiBasicExam ?
Sure, there's much "know how/that X" but besides that it pretty much nails down the scope i would intend for a basic exam and not more than 3 days to learn for a newby.
Looking foward to hearing from you,
Toni
Re: OSGI exams
Hi Toni,It's not bad at all.
My two main suggestions for now are:
1) Create sub-categories (with smaller amount of questions) within your 3 categories.
2) Try to formulate your objective points in term of abilities. It's more difficult with theoretical exam than for practical topics.
This is an example for point 2.
Imagine an exam about the theory of reproduction.
Wrong: Know that females give birth to babies.
Better: From a selection of genders, idendify which can give birth.
Other possibility: Grab a female and make her pregnant. This last one is wrong because the exam is not about the ability to reproduce but about the knowledge of reproduction.
I hope this helps.
John.
Re: OSGI exams
hi john,i just refined the sections and the objectives itself.
Toni
Re: OSGI exams
The form is very good to me Toni, you've got it.About the content, I cannot tell: I know nothing about Osgi.
Thanks you for your contribution.
Henryk, can we put this exam on-line ?
John.
Re: OSGI exams
HiDone.
Toni, thank you for the great job. We would be grateful if you decide to share more knowledge with our community in the future
Best regards.
Re: OSGI exams
who has write access to the exam objectives at jbb?In this beginning stage there are some changes to the objectives to be done. - but i cannot alter the objectives myself - so who can?
kind regards,
Toni
Re: OSGI exams
Hi Toni,Now you are moderator.
Don't you see the "Edit objective text" link from the usual exam page ?
http://www.javablackbelt.com/QuestionnaireDefDisplay.wwa?questPublicId=01609
Re: OSGI exams
Hi Toni and all others,I just started to collect stuff for a OSGi Service layer exam but there is less time at the moment.
How can I support you with your basic exam?
Greets
Christoph