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Falling Standards?

Chetan Parekh
Ranch Hand

Joined: Sep 16, 2004
Posts: 3636
I have interviewed around 50+ people with average experience of 1.5 year for the post of Developer.

I asked them only 3 simple questions
(1)In System.out.println(), what is System? What is out? What is println?
(2)What is JVM, JDK, JRE?
(3)What is the Servlet life cycle?

Why not a single candidate was able to give convincing answers?

Are we running short of skilled worker? Or people don�t want to study concept in depth?


My blood is tested +ve for Java.
Manish Hatwalne
Ranch Hand

Joined: Sep 22, 2001
Posts: 2578

Originally posted by Chetan Parekh:
I have interviewed around 50+ people with average experience of 1.5 year for the post of Developer.

I asked them only 3 simple questions
(1)In System.out.println(), what is System? What is out? What is println?
(2)What is JVM, JDK, JRE?
(3)What is the Servlet life cycle?

Why not a single candidate was able to give convincing answers?

Are we running short of skilled worker? Or people don�t want to study concept in depth?



Anybody and everybody is trying to get into J2EE development these days without proper knowledge and all they are concerned about is "How much can I expect from XYZ for my expereince. I have even funnier stories to share about interviews - maybe later...

- Manish
Anand Prabhu
Ranch Hand

Joined: Dec 19, 2003
Posts: 299
I too went through the same experience as you. I guess the "good guys" have been taken. And the Indian companies have so many projects on their plate and the number of qualified and experienced candidates being less, it's "take the best from the worst" right now.
Sandeep Ghosh
Ranch Hand

Joined: Jan 23, 2002
Posts: 145
I take at least 5 interviews a day for an onsite project. I would feel lucky if I manage to select 1 guy in 2 days and the requirement of that project is 30+. I believe the reason is now most of guys are interested in knowing how much he is worth in next job, than learning what is coming next in Java. I am not saying knowing first one is not important, but ��
Kj Reddy
Ranch Hand

Joined: Sep 20, 2003
Posts: 1704
Originally posted by Chetan Parekh:
I have interviewed around 50+ people with average experience of 1.5 year for the post of Developer.


Unfortunately it is happening with more experience people also. Once I took interview of a guy who is having 3 years experience. He told that he involved design, coding, testing, requriements gathering and what not. We asked him a question if he is using threads in his project, he said yes and when we asked why you are using thread he told his team leader told to use thread he is using threards. And what ever question we ask(especially design related questions) he is saying same kind of answer that his team lead asked to do that and when we asked what did you design-- then no answer from him.
Kj Reddy
Ranch Hand

Joined: Sep 20, 2003
Posts: 1704
Originally posted by Manish Hatwalne:

they are concerned about is "How much can I expect from XYZ for my expereince.


Even I could see this kind of mentality with many people whenever I take interviews. I see people coming to interview who already changed 3 to 4 companies in 1 or 2 years.
Mandar Max
Ranch Hand

Joined: Mar 14, 2006
Posts: 38
Isn't there any screening process (some kind of technical test) before people appear for interviews in these companies?


"The trouble with doing something right the first time is that nobody appreciates how difficult it was!"
Theodore Casser
Ranch Hand

Joined: Mar 14, 2001
Posts: 1902

Originally posted by Mandar Max:
Isn't there any screening process (some kind of technical test) before people appear for interviews in these companies?


I suppose it really depends on the company. I know as far as our firm is concerned, we don't really have the resources to put together some kind of technical test before they come before us, but hope that we can successfully screen out the unqualified ones before they come in for the interview. (That's also why we usually have three or four folks in the interview, to be able to hit a good mix of technical questions while they're in front of us.)


Theodore Jonathan Casser
SCJP/SCSNI/SCBCD/SCWCD/SCDJWS/SCMAD/SCEA/MCTS/MCPD... and so many more letters than you can shake a stick at!
Kj Reddy
Ranch Hand

Joined: Sep 20, 2003
Posts: 1704
Originally posted by Mandar Max:
Isn't there any screening process (some kind of technical test) before people appear for interviews in these companies?


Most of the companies have screening process, some times screening process may not give better results.
Chetan Parekh
Ranch Hand

Joined: Sep 16, 2004
Posts: 3636
Originally posted by Mandar Max:
Isn't there any screening process (some kind of technical test) before people appear for interviews in these companies?


We had an objective test of Java that a candidate has to clear. Test is of 60 marks and passing marks is 30. Nobody was able to clear the exam, so we reduced passing marks to 20 � rarely anybody was able to clear at 20 marks. So we further decreased to 15.
Mandar Max
Ranch Hand

Joined: Mar 14, 2006
Posts: 38
Originally posted by Chetan Parekh:


We had an objective test of Java that a candidate has to clear. Test is of 60 marks and passing marks is 30. Nobody was able to clear the exam, so we reduced passing marks to 20 � rarely anybody was able to clear at 20 marks. So we further decreased to 15.



Then probably you should decrease the standard of your interviews as well . Try to find even simpler questions than your original three...
Chetan Parekh
Ranch Hand

Joined: Sep 16, 2004
Posts: 3636
Originally posted by Mandar Max:

Then probably you should decrease the standard of your interviews as well . Try to find even simpler questions than your original three...


I guess a day will come when we will be just asking the spelling of Java � if candidate able to spell the word properly, he will get offer letter on the spot.
mohit junejaa
Ranch Hand

Joined: Feb 24, 2006
Posts: 41
Originally posted by Chetan Parekh:


We had an objective test of Java that a candidate has to clear. Test is of 60 marks and passing marks is 30. Nobody was able to clear the exam, so we reduced passing marks to 20 � rarely anybody was able to clear at 20 marks. So we further decreased to 15.


hi i m a fresher
are the qs asked during interview tougher than SCJP?
also i will be grateful if u could tell me a sample difficult question frm the exam which not many were able to answer
i guess it will help me judge my control over language


scjp 1.4
Al Hollis
Ranch Hand

Joined: Dec 12, 2005
Posts: 60
Maybe i should start looking for java jobs again. I could answer all the questions in this thread and more. Unfortunatly no one seems to want people without industrial experiance
[ May 24, 2006: Message edited by: Al Hollis ]
Tim Holloway
Saloon Keeper

Joined: Jun 25, 2001
Posts: 16145
    
  21

Sadly, the whole thread sounds just like the U.S.


Customer surveys are for companies who didn't pay proper attention to begin with.
Sri Ram
Greenhorn

Joined: Apr 04, 2006
Posts: 10
Well i have the other side of the story, there are some interviewers who donno what to ask

I have 2 yrs exp in Java/J2ee, I attended an interview with a big MNC 6 months back ,the guy who interviewed me for Java Position asked me all SQL and PL/SQL questions, i clearly told him im not an expert in SQL and PL/SQL,i know only basic knowledge on both and I have been working on Java/J2EE, he never bothered to listen

He started asking questions like how will you make sure that only authorised users are allowed to execute a query and so on , and atlast just as a formality he asked me a Java Question

How will you find the memory that an object occupies after being created in java 1.4

I said we have to write some kinda program to solve this by using system and Runtime classes

he said he wanted a single method in the java1.4 API to do this


and thats all the interview was over

that was really a shocking experience for me, i thought that guy is an , no more words to describe it
Arjunkumar Shastry
Ranch Hand

Joined: Feb 28, 2005
Posts: 986
Originally posted by Srinath Ramasubramanian:

How will you find the memory that an object occupies after being created in java 1.4
I said we have to write some kinda program to solve this by using system and Runtime classes
he said he wanted a single method in the java1.4 API to do this
and thats all the interview was over

The only conclusion you can draw from this situation is that guy must had been digging hard for 15 days to find that method.One day before he got the answer and you were the 'unfortunate' to go there next day!!
Problem with interviews in India are,interviewers are obsessed about how much the opposite guy knows about theoretical knowledge of that subject.This obsession comes from the fact that we are told that everything about knowledge is in books and practical experience carried little value.Thats the reason why many Indian companies too are much interested in your grades.


Namma Suvarna Karnataka
Jeroen T Wenting
Ranch Hand

Joined: Apr 21, 2006
Posts: 1847
That's not just a problem in India but everywhere where candidates are placed opposite HR staff for technical interviews rather than technical staff.

The HR staff have little or no technical knowledge and are working from a script prepared for them by the technical staff.
That's just a list of questions and required answers, and they'll just tick off the ones you get right (or wrong). Any score under X% is an automatic blacklisting for the next round of interviews.
Same with your resume before you even get to an interview. If you don't have the necessary buzzwords as provided by the department head to HR listed there you won't even be invited (with the result that many people try to cram as many buzzwords and acronyms into their resumes as they can come up with).

are the qs asked during interview tougher than SCJP?

If you think those 3 questions are tougher than the SCJP exam I wonder where you've taken the exam...

Sadly, the whole thread sounds just like the U.S.

That's because a lot of those candidates will get hired by some bodyshop and sent to the US on H1b visa as "Java experts", and end up desperately hopping from one job to the next to keep their status.

P.S. any idea what that method call in the standard API is to get memory allocation amounts for object instances?
AFAIK it doesn't exist. Java is all about not having to care about such details, and as a result there's nothing in the obvious places (Object, Class, ClassLoader).

There IS something in the 1.5 API in the java.lang.instrument.Instrumentation interface, there's as far as I can see no implementation of that interface provided in the standard API (and the description says it requires special JVM parameters to work at all).
Probably used by jconsole.

There are some memory monitoring functions in Runtime, but they're purely interested in JVM memory, not object instance memory (though someone might think that 2 calls to one of them, directly before and directly after object instantiation would yield the memory used by that object).


42
Mark Herschberg
Sheriff

Joined: Dec 04, 2000
Posts: 6037
Originally posted by Theodore Casser:
I suppose it really depends on the company. I know as far as our firm is concerned, we don't really have the resources to put together some kind of technical test before they come before us


I created such a test in an hour. I got the idea from google who would have their HR ask 3 questions in an initial phone screen. One question google would ask is "What is 2 to the 10th power?" If the candidate didn't give the correct answer in 5 seconds, the candidate was rejected.* (4, 3, 2, 1... did you get it?)

I made up a list of 10 questions I had our receptionist ask of candidates after I screened their resumes. This included questions like "Are you a US Citizen, greencard holder or oherwise eligible to work without a visa?" as well as well as simple technical questions, such that our non-technical receptionist could then check the candidates' answers against the answer sheet I gave. It worked out quite well.

*I was shocked to learn that google would screen with such a trivial question, thinking over 95% of the people should be able to answer correclty; however, the guy who created the screen said it worked well. I included that question on my screen and a surprisingly low perecentage was able to answer correctly (even in over 5 seconds). BTW, google regularly modifies the questions since they quickly become public knowledge.


--Mark
Rubens Gomes
Greenhorn

Joined: Apr 26, 2005
Posts: 22
I think interviews should be focused on one's prior project experience and what he/she did at those projects. Then, ask a technical question here and there. Not the other way around.


Rubens Gomes<br />SCJP 1.4 (96%)<br /><a href="http://www.rubens-gomes.com" target="_blank" rel="nofollow">www.rubens-gomes.com</a>
gopal venu
Ranch Hand

Joined: Jan 06, 2006
Posts: 55
Hi Guys,

I am having same kind of exp. recently.I am having 2 yrs exp in Core Java,JSP,Servlet,JDBC. I am also having SCJP 100% ,i think i am very good at Core Java .

Recently i had attened one of the known Indian based MNC Walk-in Interview.
Interviewer asked me lots of question and i carried them out step by step to depth up to classloader,Soft Refrence,Reflection .....like advance subjects.

And i am sure they r satisfied with the core java knowledge of mine.But then they asked me about EJB....for that i told them i dont have ny exp with EJB,Webservices....but i can learn it fast as my core java is strong.

But with my surprise those guys say ok and told me to leave.

Then HR told me that i am rejected......

I dont know why but some of my friends just read Interview FAQ and passed out...
Kj Reddy
Ranch Hand

Joined: Sep 20, 2003
Posts: 1704
Originally posted by gopal venu:

And i am sure they r satisfied with the core java knowledge of mine.But then they asked me about EJB....for that i told them i dont have ny exp with EJB,Webservices....but i can learn it fast as my core java is strong.


Some times interviewrs ask questions in the areas which you do not mentioned in your resume to just test your awareness in those areas.


I dont know why but some of my friends just read Interview FAQ and passed out...

Yes many interviews can be cleared just by reading some FAQ. Especially I know one of big company, they always asks what are the transaction attributes? If you answer that question you are selected and they don't bother much about how you answered other questions .
Rambo Prasad
Ranch Hand

Joined: Feb 23, 2006
Posts: 628
Another problem is asking all sorts of irrelevant questions not related to the kind of work that one is supposed to be working on....
There are lot of stupid interviewers who would questions related to advanced data structures,operating systems etc... for a guy seeking testing position...

Many interviewers need to educate themselves properly before asking the questions...


Helping hands are much better than the praying lips
Chetan Parekh
Ranch Hand

Joined: Sep 16, 2004
Posts: 3636
Originally posted by Rambo Prasad:

Many interviewers need to educate themselves properly before asking the questions...


In 2005, I have given a telephonic interview at Mastek, Mahape. I have developed a project that manages inventory of Petrol Pump (Filling Station) chain. He asked me a question that, what do you think, how many petrol pumps should be there in Mumbai? I said, I don�t have any idea and i can�t determine the ideal count of petrol pump in a given city � as I am not expert of that domain. Then he tortured me on the same topic for 15 minutes. Other questions are aslo on the same direction. There were harldy any technical question, he asked me all wierd questions. If i would have got the offer, I would have ask HR not to put in a team leaded by my interviewer.
Rambo Prasad
Ranch Hand

Joined: Feb 23, 2006
Posts: 628
In 2005, I have given a telephonic interview at Mastek, Mahape. I have developed a project that manages inventory of Petrol Pump (Filling Station) chain. He asked me a question that, what do you think, how many petrol pumps should be there in Mumbai? I said, I don�t have any idea and i can�t determine the ideal count of petrol pump in a given city � as I am not expert of that domain. Then he tortured me on the same topic for 15 minutes. Other questions are aslo on the same direction. There were harldy any technical question, he asked me all wierd questions. If i would have got the offer, I would have ask HR not to put in a team leaded by my interviewer


The question is a small variant of the question that is asked in microsoft interview..How many pertol stations are there in US?But Mastek is not a company which can compare itself with microsoft ..neither the pay is that great nor the work...

Lot of interviewers themselves,have a half baked knowledge,they read something before the interview and ask some questions on whatever they have read...Some of them know only to ask questions ,but dont know the answers....

To top it all asking the HR to ask questions is ultimate stupidity...Some of the HR's are really irritating bit***$....They ask all sorts of irritating questions....In my campus interview I cleared the technical interviews of SAP and at last attended a HR interview...She kept asking questions which irritated me and I started replying in a sarcastic manner....and ultimately I was the only guy who was rejected in the HR round...
But anyways now am in a better company than that....
[ May 25, 2006: Message edited by: Rambo Prasad ]
Arjunkumar Shastry
Ranch Hand

Joined: Feb 28, 2005
Posts: 986
Originally posted by Chetan Parekh:

how many petrol pumps should be there in Mumbai? I said, I don�t have any idea and i can�t determine the ideal count of petrol pump in a given city � as I am not expert of that domain.

Although this is not very good question,one can try like this,
1)In every suburb,there could be at the most 3 petrol pumps.(In theory they could be 100 but if you have visited many suburbs,you will find 3,at the most 4.
2)On western side,there are 21 stations,so 84 petrol pumps,100 at the most.
3)On central side,there could be more,say 125 as suburbs are more.
So maximum petrol pumps could be not more than 250.(I have kept this big margin bacause petrol pumps are allocated on how much money you throw on Petroleum ministry and not on population basis.)
Chetan Parekh
Ranch Hand

Joined: Sep 16, 2004
Posts: 3636
Well I felt to give estimation based on population of Mumbai.

But he was aggressively irritating since the beginning of the interview � it was clear from his way of talking that by one or another mean he just want to burn candidate�s ass.
Vishnu Prakash
Ranch Hand

Joined: Nov 15, 2004
Posts: 1026
Hello Ranch mates

Can you please post some interesting and usually expected interview questions(in Java/servlets/jsp). This will help aspiring candidates like me to have a upper hand in interview.

Thanks


Servlet Spec 2.4/ Jsp Spec 2.0/ JSTL Spec 1.1 - JSTL Tag Documentation
Tim Holloway
Saloon Keeper

Joined: Jun 25, 2001
Posts: 16145
    
  21

I've gotta call shenanigans on Jerome. Pretty much everything said in this thread has been true since long before offshoring. Chalk it up partly to Sturgeon's Law (or, as TFA calls it, Sturgeons Revelation).

I'm old, decrepit and senile, but to me, both the ability to emit the value of 2 to the 10th power and the size of a particular Java Object show the antiquity of the inquirer. I can disassemble mainframe core dumps in my head, but I had to count 2^10 out on my fingers - relatively little I do these days is still hung up on the infamous powers of 2. Now not being able to give out 10^2 in 5 seconds is a different matter.

Similarly, the exact size of a Java object is only of concern to me once I've accumulated a million or so of them and have to start economizing. Otherwise I'm wasting my time prematurely optimizing parts of the system that may not ever need to be optimized.

Of the two camps - clueless applicants and clueless interviewers, I rate the clueless interviewers as the more dangerous. A new hire that doesn't measure up can be discharged during the probationay period (at least unless you're in France). OTOH, if you're mindlessly filtering out talent, it's the company that suffers.

And people like me get filtered out real easy. I'm not a good little rat who's run the maze to perfection. I'm someone who works on initiative. I look for the roads less travelled and find out where they lead. I get called in when the good little rats can't hack it. Unless, of course, I was never hired at all.
Mark Herschberg
Sheriff

Joined: Dec 04, 2000
Posts: 6037
Originally posted by Rambo Prasad:
Another problem is asking all sorts of irrelevant questions not related to the kind of work that one is supposed to be working on....
There are lot of stupid interviewers who would questions related to advanced data structures,operating systems etc... for a guy seeking testing position...


Define advanced data structures? I absolutely refuse to hire anyone who can't explain things like binary tree or hashtable. They don't have to remember every property (that's what books are for) but they at least need to understand what they are and when to use them (otherwise they won't even think to apply them to a given problem they may come across).

--Mark
[ May 25, 2006: Message edited by: Mark Herschberg ]
Mark Herschberg
Sheriff

Joined: Dec 04, 2000
Posts: 6037
Originally posted by Chetan Parekh:
In 2005, I have given a telephonic interview at Mastek, Mahape. I have developed a project that manages inventory of Petrol Pump (Filling Station) chain. He asked me a question that, what do you think, how many petrol pumps should be there in Mumbai? I said, I don�t have any idea and i can�t determine the ideal count of petrol pump in a given city � as I am not expert of that domain. Then he tortured me on the same topic for 15 minutes. Other questions are aslo on the same direction. There were harldy any technical question, he asked me all wierd questions. If i would have got the offer, I would have ask HR not to put in a team leaded by my interviewer.


It's a fantastic question and if I candidate couldn't answer, while that wouldn't be a deal breaker, I would see it as a black mark. This type of question if sometimes referred to as a Feynman Number. There are many variations on these problems. The point of the question is not to see if you know the answer, but rather to see how you think about the problem (as you see below.)

I was once asked about the annual population growth in Mexico. I answered it as follows...

1) I don't know the population of Mexico, but there are approximately 17M people in Canada, and 300M in the US. Mexico is somewhere in between. (The interviewer offered up a population of 50M.)
2) The average life expectancy in the US is about 76. It is presumably lower in Mexico given the living standards and health care. It is probably somewhere in the 50's or 60's. Assuming a uniform distribution of ages, that means somewhere between 500,000-1,000,000 people die annually in Mexico.
3) The hispanic population in the US (which has a large Mexican component) is the fastest growing population segment, suggesting a high birth rate, probably around 3-4 kids per family, and maybe higher in Mexico.
4) Given that people have kids in about a 15 years span, and have 4 kids, we assume people have on average 1 kid every 4 years during that time, ot 1/4 child per year. There are approximately 15M people in that range at any time. This means there are about 4M births annuall in Mexico.
5) 4M-1M = 3M annually. That seems a bit high, as it's 6% annual growth. The actual number is probably around 2M.

[Note: I just looked up some data at http://www.unicef.org/infobycountry/mexico_statistics.html having now redone this. Birth date for 2004 is 2.2M. Annual growth rate 1990-2004 is 1.6% which works out to about .8M annually. It was 2.6% 1970-1990)

Now I knew nothing about Mexico's annual population growth, it's not my field of expertise. But I had some general knowledge of populations and life expectance that I've picked up in newspapers or on the internet--general knowledge you can expect someone to have--and was able to dervice a ballpark answer. I could have said 500,000 or even 3-4M and it would have been fine. If I had said 15M knowing the population was 50M that would have been wrong. Every engineer should know how to do back of te envelop calculations. You do this when you estimate the number of servers needed based on project traffic patters for example, or the size of a hashtable based on usage patterns.


Other questions of this nature include:
- How many cars drive into Manhattan every day?
- How many turkeys are eaten in the US on Thanksiging?
- How many pianos in the city of Chicago?


As for the Mumbai question, I would answer it as follows.... (try it yourself before seeing my answer)

1) Population of India is 750M.
2) Mumbai is one of the larger cities so might have a population of 8M. (Here is where your local knowledge would be better than mine since you're more likely to be able to estimate this, just as I'm more likely ot be able to estimate the population of LA.)
3) Most people don't have cars, although the rate is probably higher than average in India because the population of Mumbai as more "young tech guys with disposable income" than the national average. Maybe there are 1M cars? (Again, Indians would have a better sense of this than I.)
4) A car needs gas once a week (again I don't know typical commumiting distances, sizes of gas tanks, fuel efficency standards, etc--in the US it would be roughly 30 miles, 20 gallons, 18mpg) so any given day 150,000 cars fill up.
5) A gas station might service 800 cars a day (I assume there are multipump stations open for 12 hours). That means there are approximately 200 gas stations in Mumbai.
6) For a US market like Boston, that seems very low, but I don't know the size of stations, density, etc.


--Mark
Mark Herschberg
Sheriff

Joined: Dec 04, 2000
Posts: 6037
Originally posted by Tim Holloway:
I'm old, decrepit and senile, but to me, both the ability to emit the value of 2 to the 10th power and the size of a particular Java Object show the antiquity of the inquirer. I can disassemble mainframe core dumps in my head, but I had to count 2^10 out on my fingers - relatively little I do these days is still hung up on the infamous powers of 2. Now not being able to give out 10^2 in 5 seconds is a different matter.

Similarly, the exact size of a Java object is only of concern to me once I've accumulated a million or so of them and have to start economizing. Otherwise I'm wasting my time prematurely optimizing parts of the system that may not ever need to be optimized.


Given that it comes form google, you can be sure the guys aren't that old. :-p

I think you're missing the poing of the question. It's a general question similar to "what's a CPU?" If you have worked with computers and/or studied computer science you should know what the CPU is. If you don't that's a big flag. Google uses the question in the same way. It's not perfect, but as I've noted in similar threads, the purpose of the interview process isn't about finding the best candidate, it's about finding a good enough candidate in a reasonable time for a reasonable cost.

As for the size of Java objects, I would never hire a candidate who didn't understand that (my version of this question is here). You are correct that 99% of the time that understanding is never used. But I want the candidate who does understand the issue for the 1% of the time it is relevant.

--Mark
Rambo Prasad
Ranch Hand

Joined: Feb 23, 2006
Posts: 628
Define advanced data structures? I absolutely refuse to hire anyone who can't explain things like binary tree or hashtable. They don't have to remember every property (that's what books are for) but they at least need to understand what they are and when to use them (otherwise they won't even think to apply them to a given problem they may come across).


It looks absurd to ask a tester questions like
In an array of integers (both positive and negative), how will you find the sub array with the largest sum in O(n).?
Given a pointer to the root node of a tree..Devise an algorithm to find whether the tree is a binary search tree or not?
What is red-black tree?

What is the need for him to know such things...??It makes more sense to ask a developer such questions...
[ May 26, 2006: Message edited by: Rambo Prasad ]
Ketan Joshi
Ranch Hand

Joined: Oct 09, 2005
Posts: 66
Too junior to comment on falling standards

But this question on Petrol Pumps in Mumbai remind me of the Famous

Akbar Birbal stories where the witty Birbal answered Akbars question of the number of Crows in the city.

Give any random number without really thinking about Mumbai's population etc.
If the interviewer says that your estimate is on the lower side of the reality, say that I have not considered the illegal petrol pumps which have recently come up


If the interviewer says that the estimate is on the higher side, say that probably some of petrol pumps might have recently shut down which I had counted while answering


I think these questions are good for testing presence of mind or may be some other qualities

Good question for Management Interviews may be


Ketan
Mark Herschberg
Sheriff

Joined: Dec 04, 2000
Posts: 6037
Originally posted by Rambo Prasad:


It looks absurd to ask a tester questions like
In an array of integers (both positive and negative), how will you find the sub array with the largest sum in O(n).?


Absolutely not. Look, any idiot can memorize what a keyword means, or the difference between various types of EJBs. The better developers are the ones who can solve analytical problems. As in all cases, the better interviewers will judge a candidate not on the answer, but rather the approach used to get the answer.

I can't speak for others byt if you don't know how to think through a problem, you have no place in my company.

--Mark
Tim Holloway
Saloon Keeper

Joined: Jun 25, 2001
Posts: 16145
    
  21

Actually, I don't know how big a (whatever) Java object is. Unless I missed something, it's up to the JVM implementor. In practical terms, that probably differs between Sun's JVM and IBM's and the new Linux JVM, etc. etc. In theoretical terms, I can right off the top of my head think up about 5 different ways to store objects, some of which are nonlinear with respect to the number of objects, and a few of which are extremely nonlinear with respect to the number of such objects. So don't be surprised if I respond with the famous quote:

An African swallow or a European swallow?

It's not entirely theoretical, either. Remember, Java plays funny games with immutable strings and boolean constants, so the correct answer in some cases is zero.

See why people don't like me? Tests don't simply test your knowledge, sometimes they test your ignorance, as well.

Seriously, the default memory footprint for Tomcat 5 is 256kM (give or take 128M). We started seeing occasional OutofMemoryExceptions on our most critical server. The machine has 2GB RAM, uses a little over 1GB, runs about 16% average CPU workload. So I checked the failing app for memory leaks, found none and bumped it up 128MB. End of story. If I'd sat down and calculated per-object memory usage, my boss would've killed me - I do too much of that kind of thing already, he says. He was much happier when I took a database run went for 3 days, did 2 days redesign work and made the run drop to 20 minutes. I've I've got my math right, that was about a 6000% speedup. So I've still got a job.

Actually, I spent several weeks last July dealing with a memory leak. This job took 5 days to churn through a database and would blow after 3. I took lots of snapshots, gave the HAT tool a nervous breakdown, ended up having to hand-track who allocated what. Discovered the culprit was an Oracle "cache" class that was implemented as an open-ended list; never released anything. Changed some options and no more memory leaks. I also reduced the 5 days down to 14 hours worst-case, 30 minutes typical. Never did check to see how big the objects were. It didn't matter, since the problem was that there were too darn many of them. They weren't mine to resize, anyway so it wouldn't have mattered.



Aw what the heck. As long as I'm annoying people:

It's all very well to make an estimate, but when you start adding more and more refinements it actually diminishes my confidence in the results. It may look impressive, but what will it do to the final results? Just because Mexico shares a continent with the U.S.A and Canada doesn't mean that their populations have any correlation. In my case, I'd have to start with the knowledge that Mexico City alone has something like 12 million inhabitants, so potentially Mexico could have a larger population than the U.S.A. I wouldn't even dare to extrapolate population growth from there.

Similarly, I'd expect to discover that consumption patterns for petrol vary widely - if it's like most things, 80/20 or 90/10. The U.S.A. is infamous for its ability to drink gasoline in quantity out of proportion to is population - how much more so for a place like India where so many people are still village agricultural? Even within population centers, I'd expect to find a wide variance in how much business a given pump handles. Would you believe that one of the 10 busiest fire stations in the country is located in my town even though we rank somewhere around 50th in population?

I'll give credit for cleverness, but far more credit to someone who'll actually look it up.

But I'm not complete contrary. If you don't know what System, out, or println are, you still don't get the job. And that one you don't get to look up.
Mark Herschberg
Sheriff

Joined: Dec 04, 2000
Posts: 6037
Originally posted by Tim Holloway:
Actually, I don't know how big a (whatever) Java object is. Unless I missed something, it's up to the JVM implementor.


I'm sorry Tim, that is such a poor answer. An int is 32 bits. Sure, the JVM *can* store each int in 1 full meg of storage, but that's just stupid. It's areasonable assumption that most JVMs oprate reasonably efficently. It's also reasonable to say that a 10,000,000 lenght array of ints takes up approx 40,000,000 bytes, and if you don't have enough memory for that it will pagenate. And if you can't figure that out you'll be writing slow code.

We use abstraction layers in CS, but the best people know what's on the other side. Do you think the best race car drivers simply know how to press down on the gas petal faster than anyone else? They understand how the pistons work, the response time on the fuel injection system, etc. I expect the same from my development team.


Originally posted by Tim Holloway:
Just because Mexico shares a continent with the U.S.A and Canada doesn't mean that their populations have any correlation. In my case, I'd have to start with the knowledge that Mexico City alone has something like 12 million inhabitants, so potentially Mexico could have a larger population than the U.S.A. I wouldn't even dare to extrapolate population growth from there.


We'll I'd say if I were estimating the population of Laos it makes sense to consider that of Vietnam and Malaysia more than to compare it to that of Lyberia and France. The cultures are more similar. you could argue that Guatamala and Spain might be better countries, but since I only happen to know the population oft he US, Canada, China, and India that's what I had to work with. The former two seemed like a better fit than the latter two, especially since the first had a non-trivial Hispanic population.

But that's not really the point. The point I explain below...

Originally posted by Tim Holloway:
Similarly, I'd expect to discover that consumption patterns for petrol vary widely - if it's like most things, 80/20 or 90/10. The U.S.A. is infamous for its ability to drink gasoline in quantity out of proportion to is population - how much more so for a place like India where so many people are still village agricultural?


You're arguing over minutia. It doesn't matter if the patterns are out of whack, or if Canada isn't the best country to use as a comparison. The point is the cnadidate can make a rational cohesive argument based on data at hand. Presumably when focused on problems within their domain of expertise (i.e. software), they will have more accurate information and assumptions. Combined with an ability to reason, you've got a great developer. I would argue reasoning is more important thatn knowledge, because it's easier to pick up the latter.

--Mark
pankaj shukla
Greenhorn

Joined: Apr 22, 2006
Posts: 21
Originally posted by Mark Herschberg:


Absolutely not. Look, any idiot can memorize what a keyword means, or the difference between various types of EJBs. The better developers are the ones who can solve analytical problems.

--Mark

Mark,
Again you are talking about the developers. The point was whether such questions should be asked from a tester.
Unless you are working for Microsoft, you are not expected to play at the developer level while being a tester.
One must not miss the big picture while delving deep into details.
Mark Herschberg
Sheriff

Joined: Dec 04, 2000
Posts: 6037
Originally posted by pankaj shukla:

Mark,
Again you are talking about the developers. The point was whether such questions should be asked from a tester.
Unless you are working for Microsoft, you are not expected to play at the developer level while being a tester.
One must not miss the big picture while delving deep into details.



I'm taking the phrase "asked from a tester" to mean "using to interview a tester." (If I am misunderstanding you please correct me.)

The same arugment applies to both. In both roles (and in most roles) I want logical people who can use facts to reach a conclusion.

--Mark
Manish Hatwalne
Ranch Hand

Joined: Sep 22, 2001
Posts: 2578

Originally posted by Mark Herschberg:

The same arugment applies to both. In both roles (and in most roles) I want logical people who can use facts to reach a conclusion.

--Mark


Exactly!!!
Problem solving ability has to be the most important thing to be tested.

- Manish
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: Falling Standards?