Multithreading concepts : java.util.concurrent package: Interview preparation

[Prajakta Acharya]

Hi friends,

I am having a project interview within next 2 hours and I got to know that the project requires knowledge of caching and multi-threading.

I am comfortable reading caching concepts from net but as far as mult-threading goes, especially the concurrent package, I would need some time to grasp the concepts easily.

So its my request to point me to simple/easy to understand material regarding this or explain me in short.

Thanks in advance.

[Ivan Jozsef Balazs]

How To Ask Questions The Smart Way by Eric Steven Raymond

Don't flag your question as “Urgent”, even if it is for you

That's your problem, not ours. Claiming urgency is very likely to be counter-productive: most hackers will simply delete such messages as rude and selfish attempts to elicit immediate and special attention. Furthermore, the word 'Urgent' (and other similar attempts to grab attention in the subject line) often triggers spam filters - your intended recipients might never see it at all!

There is one semi-exception. It can be worth mentioning if you're using the program in some high-profile place, one that the hackers will get excited about; in such a case, if you're under time pressure, and you say so politely, people may get interested enough to answer faster.

This is a very risky thing to do, however, because the hackers' metric for what is exciting probably differs from yours. Posting from the International Space Station would qualify, for example, but posting on behalf of a feel-good charitable or political cause would almost certainly not. In fact, posting “Urgent: Help me save the fuzzy baby seals!” will reliably get you shunned or flamed even by hackers who think fuzzy baby seals are important.

If you find this mysterious, re-read the rest of this how-to repeatedly until you understand it before posting anything at all.

[Jeff Verdegan]

If you're cramming at the last minute before an interview, you are in effect trying to deceive the interviewer into thinking you are more qualified for the job than you actually are. If your answers manage to impress him enough to land you the job, then what? You won't actually have learned and come to understand the topics enough to do the job just from the cramming, and now you're getting paid to do a job that you're not competent to do.

It's fine to brush up on stuff that you're familiar with but have forgotten the details of, but it is a disservice to the employer, to other candidates, and to yourself to pretend you know more than you do, not to mention being highly unethical

[Gaurav Raje]

In the long run, you might want to consider reading http://www.amazon.com/Java-Concurrency-Practice-Brian-Goetz/dp/0321349601/ref=sr_sp-atf_title_1_1?s=books&ie=UTF8&qid=1370635844&sr=1-1&keywords=java+concurrency

I lovced this book. It will start from the concepts and take you to some intermediate level stuff. Though, in any case, the best teacher is to do a project.

[Prajakta Acharya]

Hi Jeff,

Thank you for making me understand the ethics.

But I want to throw some light on this, from my perspective.

Firstly,I am an experienced Java developer who has extensively worked on various development projects and I have consistently proved my development abilities.
I have worked on many new frameworks which were new to me and have enough confidence that I can grasp new things on job.

Secondly, I am already employed and was preparing for a client evaluation.

From my experience I have noticed that some people want exact match to their requirements and want hands on on that particular sub-technology.
In my opinion, it is not always possible to have hands on on each and every framework and there is first time for everything. That should not stop you from aspiring for a good project.
It is the responsibility of the employee to keep sharpening the saw, as far as technology is concernced and I am already aware of these things.

And of course, interviewers are smart enough to judge capabilities of the interviewee. So in no way is my attempt to fool anyone and survive.

As far as multi-threading goes, I have some prior experience on executor service and wanted to brush it and understand better.
So before reaching any conclusions about anyone and posting it on public forum, it is my humble request to verify the background.

[Vivek Hingorani]

Yeah I agree with Prajakta. Its easy to comment on anyone. I do have went through same situation and can easily relate.
In one manager round interview i was told to code a problem statement and given 10 mins for the same. I solved it but it took me around 20 mins and I was rejected in the same. It feels very sad when something like this happens..

[Chan Ag]

"If you're cramming at the last minute before an interview, "


Do you notice the 'if' in his sentence?

[Henry Wong]

Prajakta Acharya wrote:
I am having a project interview within next 2 hours and I got to know that the project requires knowledge of caching and multi-threading.

As a side note... 2 hours?!?!? Seriously?!?!? You expected an answer, and have time to digest that answer, along with any further research, for an interview in 2 hours?

As you probably already figured out by now, a forum doesn't behave to urgent questions very well.

Henry

[Jayesh A Lalwani]

Multi threading is something that is hard to learn from a book, much less understand it over forum posts in 2 hours. Yes, you can understand the tools available to you, but being able to use the tools requires knowledge of underlying concepts, issues and strategy. You can never learn that in 2 hours, and, in an interview, it's easy to identify someone who hasn't done multi-threading programming

IMO, if you have a job requirment that is strongly asking for multi-threading in it's requirement, and you are coming on here 2 hours before the interview, you are better off canceling the interview. If the job req says knowledge of multi-threading is "nice to have", you are better off being honest, and just telling them "this is what I know, this is what I don't know, I am willing the learn"

[Jeff Verdegan]

Prajakta Acharya wrote:
Firstly,I am an experienced Java developer who has extensively worked on various development projects and I have consistently proved my development abilities.
I have worked on many new frameworks which were new to me and have enough confidence that I can grasp new things on job.

Then that's what you should tell the interviewer, along with, "While I don't have any direct experience with multithreading, when I learned that it was important for this job, I started studying it. I expect to be able to come up to speed quickly, although I may need some guidance initially."

Secondly, I am already employed and was preparing for a client evaluation.

Okay, but that's not relevant to anything I said.

In my opinion, it is not always possible to have hands on on each and every framework and there is first time for everything. That should not stop you from aspiring for a good project.
It is the responsibility of the employee to keep sharpening the saw, as far as technology is concernced and I am already aware of these things.

I agree completely. But that doesn't mean you should try to come off during an interview as more knowledgeable than you really are.