learning java

[miah]

Those are actually decent questions, I wish more people doing interviews went into that type of detail.

-miah

On Thu, Apr 29, 2004 at 12:37:29PM -0400, Duane Morin wrote:
> On Thu, 29 Apr 2004, Adam Russell wrote:
> > Just curious, what sort of technical questions do you ask candidates for java positions? 
> 
> Ok, I'll get into this if people promise not to jump on every last 
> question and say "What? You'd not hire me because of THAT?  You suck".
> We gotta think big picture here, people.  I like to think of these 
> questions as "poking stick" questions.  You poke aruond, and when you find 
> what looks like a gap, you then have an avenue to pursue.
> 
> Also, of course there's no consistency.  I've seen places where you get a 
> written exam.  We don't do that. I ask the questions I think are gonna 
> give me the kind of reading I want.  The guys that come after me ask 
> different questions.
> 
> Random sampling of questions...
> 
> * Can you tell me what constitutes a well-formed XML file?  (Since I got 
> so much arugment over the 'triviality' of this question I changed it to 
> drawing a bad XML file on paper and asking people to tell me why it is a 
> bad XML file)
> 
> * When working with servlets, what's the difference between a redirect and 
> a forward?  What is a servlet filter and how is it different from a 
> servlet forward?
> 
> * Given a primitive such as an int or long, write some real code to count 
> the number of bits that are set.  This is one of my favorite questions, 
> because there are a variety of creative ways to go about it just from a 
> problem solving perspective, and you can also talk about different ways to 
> optimize it (for size/speed).  Sure, the problem as described is trivial, 
> but it's a toy problem.  And if somebody says "Wow, that's dumb..." then 
> I've already laerned more about their attitude than I need to know ;).
> One of the best answers I ever got was somebody that told me three 
> different ways to answer it, the pros and cons of each, and then chose 
> one and wrote that.
> 
> * Reverse a singly-linked list.
> 
> * I have a list of several million strings, but I know that there are only 
> about 100k unique ones.  I want to make myself a frequency table that 
> tells me how often each string occurred.  Write me a data structure to do 
> it.  Everybody makes a hashmap, which is fine, but most people end up 
> creating several million Integer objects when it can be done by only 
> creating 100k.
> 
> * Crawl all the HREFs out of a given HTML file.
> 
> * Tell me about the differences between Vectors and arrays and examples of 
> when each might be useful.
> 
> * How would you implement an LRU cache?
> 
> 
> If I ask somebody to write code it is always for a 'toy' problem that can 
> be easily encapsulated and written in like 10 minutes.  It's always 
> interesting to see people who claim to write Java every day get flustered 
> over some pretty basic stuff.  And I'm not talking about memorizing the 
> API (although I'd like to think that everybody knows how to get/put a 
> hashmap), I"m talking about Java syntax like this:
> 	
> 	boolean table[arr.length];
> 	for (int i =0; i < table.length; i++) {	
> 		table[i] = false;
> 	}
> 
> That's wrong and redundant, btw. :)  Or this:
> 
> 	if (map.contains(s)) {
> 		map.put(map.get(s)++);
> 	}
> 
> which is wrong in more than just a "not memorizing the API" way.
> 
> 
> 
> Hope that was interesting to you.  I get nervous when this subject comes 
> up because it always turns into a flame war over what is ok to ask and 
> what's useful or not.  I wasn't kidding when I joked that "If I need to 
> know that I can look it up on google" is a very common response.  By that 
> logic I could do brain surgery but nobody seems to be willing to write me 
> a paycheck.
> 
> Duane
> 
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