Henry Naftulin

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since Feb 08, 2010
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Recent posts by Henry Naftulin

Android User Interface Development - Is it easier/ harder than Blackberry UI development? How close are the libraries to regular java swing libraries? What prior knowledge does the book assume?
10 years ago
I am planning to take Spring Certification soon. I know that I need to take a class, but besides the class which books would you recommend for the study? Does Pro Spring Integration cover the topics of the certification?

Henry
10 years ago
I am thinking about Spring certification. Good question!
Hello fellow ranchers,

For those who took Spring class and passed Spring certification - was it a useful experience? Was the class good, worth the time? Need to figure out whether to pursue the certification and if so, how to convince the company to pay for the class.

Thank you in advance for your responses,

Henry
10 years ago
Got an e-mail from Oracle last week informing me that I had passed the exam. Thank you very much for your support!!

In terms of perparations: I posted my notes on the first exam about mid last year. It took me about 80 hours spread out during 3 month to prepare for part two and three. The main thing that helped me was chapter 9 of the architecture book and this forum.

Thank you again,

Henry
It looks like the thread for Horizontal scaling got side conversation on what is Reliability is, so I figured this topic deserves its own thread.

So is reliability = correctness + availability or is it something else?

Any thoughts,

Heading to part 3 exam tomorrow, so it would be great to hear your thoughts and any tips on part 3

Henry
Not too sure about more availability means more reliability. reliability - ensures the integrity and consistency of the application and all it's transactions.

So, for example, I can have very available "multiplication service" running on many load balanced boxes that instead of multiplying will give me random numbers (or even better always return 0). Now, the service will be highly available, and highly unreliable.

Am I missing something basic here?
There are a bunch of posts discussing this issue - I've seen a few without even searching for them. To summarize: most go with Cades' approach though it is not what they would do in real work assignment.
Scalability: you would be able to handle more requests with the extra server if you load balance your requests.
Availability: if one of your servers is down, second one can take the load (fault tollerance)

I was trying to get any info on what would improve reliability - and apart from unit testing software (correctness), using db transactions (correctness) haven't found much. Any ideas are welcome
thank you, that was a good read
I think it is somewhat of both. In your case, you chose to deploy it on server - but your architecture allows it to be deployed to several servers: the web components could go to web server, and EJB components could live on a application server. Usually, in J2EE application, you would also access database, which can live in its own server box, right? So, in classical J2EE architecture you have 3 tiers, even when you choose to collapse some of them for the time being.

Hope that helps,

Henry
Ludwin - congratulations and thank you!
10 years ago
yes, but it comes with a seep performance price tag, so one needs to have a convincing argument to why it is needed.