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OK I am not only new to concurrency in java but am also fairly new to java programming. I tried understanding concurrency from The java tutorials, tried reading Concurrency in practice but it seemed too advance, so tried reading from couple of other books: SCJP A comprehensive, The java programming language 4th edition.
Its as if there are things which just don't add up or make sense, I am not able to get the why's and how's and form the correct pattern of conceptual understanding. I apologize for describing this exercise in futility. But can someone please recommend good reading materials and/or ways to learn concurrency in java.
but am also fairly new to java programming
Leave the concurrency book aside for a few months and go ahead with reading a basic Java/SCJP book and practicing basic Java a lot. Create so now and then a Thread or Runnable as per the book's instructions. Play around with it for some months until you get a good grasp on it. Then continue with the concurrency book.
Learn walking before running, else you're crawling instead of running.
This sounds like you will soon be tested (class? certification?) "on Java concurrency". You have not experienced the cycle of running into a problem naturally, thinking about how to solve it, and turning to concurrency for a solution. If this is the case...
(1) Don't blame your brain. Rather, take a step back and start thinking about problems that interest you. Write them down. Internet applications are a good place to start. For example-- writing some sort of Internet server that can handle multiple connections from different users, like a game server. Or, a stock trading program that has to handle your robot's orders at the same time as processing information from the broker.
(2) Think concurrency. Now that you have a problem that interests you, and thinking of concurrency simply as multi-tasking, draw a diagram of actors/programs with arrows representing how they need to communicate with each other. Sketch out a dummy-skeleton code. You're not actually going to write a game server; but you can make a simple skeleton class library with simple, empty member functions like connectToGame(){}
(3) Now you're ready. Run a hello-world thread example or two. Flip through your books or browse the Javadocs and see the different concurrent structures that are available. Think about which ones you might apply to your problem. Don't worry about making the "right choice". You will soon find out if you've got something that works.
(4) Embrace trial and error. There is another word for it: learning!
Now, after you get some experience doing this, you'll be able to pick up a Java concurrency book and read about someone else's problem.
Hang in there and don't give up.
My favorite learning Java Book which has a great chapter on concurrency is:
Sun Certified Programmer & Developer for Java 2 Study Guide (Exam 310-035 & 310-027)
It's a difficult subject, nobody has full grasp of it, not even those who designed it.
Many people understand only a subset of it. If you only know a few tricks/patterns that you can use in your programs with confidence, that's good enough. From there you accumulate more and more.
A novice may only know that he can add 'synchronized' keyword to methods. Amazingly that solved a lot of problems and performs just fine, even if he has no idea what he is doing.
To add my two cents worth: concentrate on learning the concepts of concurrency first, rather than the machanics of actually using it in any particular language. If you get bogged down in language constructs it'll be all that much harder to get a high-level understanding of the subject.
To this end I would recommend How to Write Parallel Programs by Carriero & Gelernter (free & legal PDF download). It strikes a good balance between describing the concepts and providing concrete code examples, and doesn't get bogged down in theory. It's actually very readable and entertaining (or maybe that might be just me).
I feel like I understand concurrency backward and forward. Recently, I grabbed a book off the shelf in our office and found it was VERY good. Not just at concurrency, it gives great coverage of Java as a whole.
Introduction to Java Programming, Eighth Edition: Comprehensive Version, Y. Daniel Liang
However, most of my understanding came from experience working with code, tackling problems, and trying examples. I never truly understood threading until I did it.
Concurrency is complex and most people won't get it just from reading. Look through the API and write some test programs to try things out. Whatever book you choose, try to not just read the code, write it out and run it. After a day or two, working with it, you'll have it mostly figured out.
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I want to start making cellphone apps with Android as first choice but not the only one. I have 10 years of experience with Java, C#, C++ in commercial applications and I know that many things and practices for this applications are not valid for cellphones. Where do I start reading? How do I adapt my way of thinking to this new environment as quickly as posible? I plan to make some money with it sometime in the future as an extra income or a career change maybe, who know. Any resource or advice you could recommend will be very welcome. Thanks in advance.
Just start with Android Developer site http://developer.android.com/index.html.
It contains all you need for the beginning. Also take a look onto Commonsware android books,
those are really great both for beginners and experienced programmers - http://commonsware.com/books.html.
You could start with two great books listed as reference [1] (Ableson F. et al., Unlocking Android, 2009. Manning Publications Co., ISBN 978-1-933988-67-2) and [4] (Conder S. and Darcey L., Android Wireless Application Development, 2009. Addison-Wesley, ISBN 978-0-321-62709-4) in my degree thesis. Both have an extensive walk-through of Android, which you as a developer should know. You'll get all you need from "Hello World" to deploy an actual application in the Android Market.
Android is the place to start, since you already know Java and C# and C++. You can even use native classes in Java written in C or C++ if you have some useful standard classes in your library. More on Natives you'll find in the reference book [9] (Silva V., Pro Android Games, 2009. Apress, ISBN 978-1-4302-2647-5).
The best of luck!
Only support the TOP os's which generate income. So at this moment IOS and Android.
Don't go down the path of Symbian and Java... it's dirty, and you won't like what you see down there.
What really got me going was the Hello, Views documentation. Will really get you up and running instantly.
I recently decided studying Android, and http://developer.android.com was a great resource. You should read the Application fundamentals doc first and User Interface documentations later.
There are some tutorials too.
I read the whole Application fundamentals, and that gave me a good idea of "how to program for Android" since it has its own architecture and environment. Get the idea of Activities, Services, Broadcast Receivers and Content Providers and try to adapt yourself to that structure. Then read about how Tasks work, and later go into UI.
As a subjective opinion, being Android so popular and growing, I don't think it's worth the effort to study Java ME or even C (I'd go for iPhone devel in any case with Objective-C). Android will probably give you more money and faster. Java FX might be interesting...
iPhone
Android
Samsung Bada
I would like to mention that iphone and Android communities are very much evolved and have a great developer community and resources. Samsung Bada doesnt have a good developer network nor does the SDK support many operating systems. I think it works only on Windows.
You need to first understand the mobile platform architecture, the different frameworks which the platform exposes to the programmers to develop applications.
There are emulators for you to test, however you have to have one of those devices to do a real time on-device testing.
With respect to programming, i think your experience is more than enough but one needs to come out of the frame of mind and think differently. A typical device has limited processing power, limited memory, limited screen space but the user demands beats expectations compared to desktop/enterprise software.
Lastly most important thing is the IDEA of the application. You may want to survey existing application on the stores and start thinking. You can also develop and application which would solve your problem with mobile devices and you know other users also may want such a application.
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I need to have an at-home project now that I'm working on Python/Django at work. I'd like to learn something new, so I was thinking of checking out Java.
What's the most well respected web framework for deploying Java web apps?
The only reason I'm not checking out ruby on rails is because of how similar the ORM and other parts are to Django.
Alternatively, does anyone think I should take a look at seaside/smalltalk? Can anyone explain why I should?
Haskell is something I'll consider if anyone can make a good argument for it. I'd need a web framework and database access library to go along with it though.
I'd consider factor/forth if I wasn't so accustomed to the stack paradigm via x86/asm. I'd be willing to hear any counter-arguments to this as well.
See also: http://www.reddit.com/r/programming/comments/9v3uf/asm_c_python_perl_lisp_scheme_programmer_looking/
With that range of skills, why don't you learn something more outside your comfort zone, like carpentry or painting, or any of hundreds of other skills that have little to do with your field.
At some point, all languages are the same and you'll get scant benefit from learning another.
Whereas, with something totally different, you will become a much more well-rounded individual. I, for one, like painting and golf, even though I'm not that good at either of them - when I asked my golf instructor what my handicap was, he said it was an inability to hit the ball straight :-)
I find that I enjoy doing stuff I'm not accustomed to since it's a genuinely new experience. Learning another computer skill is a easy thing to do after a while and hence the pleasure from doing it is reduced.
Don't get me wrong, I like to keep up with developments in the field but, for the most part, the brand new technologies give nothing to my career since most work I do is on stable technologies. You may be in a different situation.
Haskell is pretty popular these days as a mind-bender, though it may not hurt as much for you if you already know Lisp and Scheme. It's purely functional, so there are no side effects to anything. You have to use monads to print text and do other things that require a certain order. It's also completely lazily evaluated, so you can make infinite lists in Haskell and not have to worry about memory consumption.
The Haskell Platform may not be fully complete, but is intended to be a portable set of libraries for Haskell. It's list of packages includes some for CGI handling and (X)HTML generation.
Sounds like you're into web programming, so smalltalk/seaside is a great one. IMO everyone should learn smalltalk even if they never use it, and seaside is a really different web framework than what you are used to. Django, fer instance, is all about REST, while the seaside philosophy basically says "to hell with REST."
And if you've never coded in an image based environment there's just something about it that seems... natural, magical even. Lots of IDE functionality that originated in smalltalk have been implemented in file based language IDE's, but it always feels like an unnatural grafting, where those same features feel as if they simply belong there in smalltalk.
Check out Pharo. Give it enough time to get used to the fact that there's no menu bar and see if it doesn't grab you.
I do suggest Java. When I was looking for a job, I noticed lots of openings for Java developers, so there's a lot of it out there, and you might someday have a chance to use your Java skills.
And then you should try out Scala. Scala is a sort of Python-ish language that uses functional programming to make very scalable programs. Unlike Python, in Scala you do need to declare types of things. Scala runs on the Java Virtual Machine so it can be used in Java shops.
http://www.scala-lang.org/
It's possible I'm just giving you this answer because these are the next two languages I intend to learn, myself.
You probably should also spend a little time playing around with Javascript. Javascript was sort of intended to be a "stealth Lisp" and I imagine you would pick it right up.
http://www.crockford.com/javascript/javascript.html
http://bc.tech.coop/blog/030920.html
And heck, have some fun with it. Write a game or something!
From your list I'd say you are due for a completely object oriented language.
You could check out Ruby, but I'd recommend JavaScript since it offers a lot of interesting things you probably wouldn't expect, like support for closures, higher-order functions and prototypical inheritance - plus it's kinda fun and becoming very popular.
I'd need a web framework and database access library to go along with it though.
If all your programming is based on web frameworks and SQL databases, you will only be solving the same problems with different syntax if you switch languages.
Build something using a different data model - Prolog, Conceptual Graphs, RDF, Linda/JavaSpaces, XQuery, HDF5, ASN.1, or a different network model - XMPP pub-sub, SNMP, a zero-config mesh or a swarm of ZigBee enabled Arduinos.
Maybe look at languages like Oz, Io or Erlang/OTP, which are distributed rather than primarily monolithic like the ones you mention.
What about the Java Spring framework?
http://www.springsource.org/
Or maybe NHibernate?
http://en.wikipedia.org/wiki/NHibernate
At the end of the day its up to you. As I only listed two out of many. When I am programming a static language professonally... I try to learn a dynamic or scripting language. And vice versa.
Also, I try to learn something totally different or outside my realm... maybe even Powershell or Korn shell or ActionScript.
What's the most well respected web framework for deploying Java web apps?
There is no single web framework more respected than others. Struts2, Spring MVC, Stripes or Wicket (which is event based) are all good candidates (I personally like Stripes). But you'll need a bit more for the persistence (Hibernate or JPA) and for the glue (Spring).
Grails (Groovy on Rails) is another good option.
Alternatively, does anyone think I should take a look at seaside/smalltalk? Can anyone explain why I should?
Well, I guess that learning Smalltalk can't hurt but I don't see a good reason to choose Smalltalk over a moderner language like Java. Regarding tooling, I don't know anything in this field except VisualAge for Smalltalk but, personally, I'd really stay far away from it.
Haskell is something I'll consider if anyone can make a good argument for it. [...]
Looks like I'm not the right guy for that.
I'd consider factor/forth if I wasn't so accustomed to the stack paradigm via x86/asm. I'd be willing to hear any counter-arguments to this as well.
Same as above.
I would have suggested mastering Lisp (in some relevant dialect) so even if you have Lisp and Scheme on your resume, it might be worthwhile to REALLY learn deeply. See http://www.paulgraham.com/avg.html for reasons why.
Otherwise Prolog might interest you. It is related to SQL but for programming instead of communicating with an organised set of data tables.
If you want to target web technologies I only have experience with Java. Here the newest Java Server Faces (JSF) allow for using Ajax to update pages, and Google Web Toolkit allow for very rich component based web pages. These might be juicy enough to interest you enough to learn enough Java to find them fun :)
I don’t see C# and the .NET platform on your list. And I am surprised no one mentioned it yet.
I have worked in C# for 5 years. I have looked at some Java code but I have never coded in it. I believe that Java is somewhat similar to C# enough so that if you become proficient in one I think you could pick up the other is a matter of a few days.
One idea might be to create your own language / compiler. The one I would like to create (or see created) would be an Assembly Language level compiler with an object oriented syntax that would be very much like Python… but make it typed language. You could start with the basic raw binary types db, dw, dd, and then add on to these … The functions and methods could have assembly language freely mixed in the high-level code. Now, that would be a fun project, I think ?
Definitely try Haskell or Smalltalk or Forth.
I would say Smalltalk would be most useful while Forth would get you away from the x86 asm and C bullshit. There's more than one way to code close-to-the-hardware stuff.
Why don't you try OCaml? And if you ever happen (sadly) to return to .NET world - you will have knowledge of F# in your baggage.
I have my first ever interview for a Java developer role, specifically RMI, Serverlets and JDBC.
However, it has been a while (2 years) since I have done any Java coding. I am sure I still have it up there somewhere and I do remember the Java syntax
I wanted to ask how can I re-fresh everything in 2-3 days specially the OOP concepts (polymorphism, inheritance) specifically to Java?
Any links, references and tutorials appreciated.
I am new to this site and I see there is a preference for programming related questions, hope I can get away with this!
Would also appreciate those that know any Java interview questions so I can go through them and test myself.
Thanks all
I'd suggest you you test yourself, e.g. on Java Black Belt, which has a good question base grouped by categories and detailled explanations for your mistakes.
I'd also recommend (re-)reading Sun's Java Tutorial and (longer) Thinking in Java by Bruce Eckel (3rd edition is free to download).
Tutorials on RMI
Java Servlet Technology
JDBC Tutorials
OOP concepts (polymorphism, inheritance): Head First Design Patterns
Java Interview Questions
How about this. Take a certification guide. It will save you a lot of time, and give you an exercise after every chapter (might give you some interview questions). You don't need to bore you down to death by teaching yourself in a wordy way, what you might already know. The best would he Khalid's Java Certification Guide. Believe me it would be faster and more effective. Plus give you the skills for appearing in the test for real, if you like to. :)
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A project I was working on has finished, so I've been moved on to some new tasking at my employer. The previous work was very agile, small team, progress over procedure, etc etc.
So anyway, the new project I'm on - I find myself confused on how to deal with management. They have no real understanding of object oriented programing , current technologies or methodologies. They seem to fear change and just recently we moved to the latest JRE
We do these code reviews and I have to listen to "gray beards" saying how much better it is in ADA or how they used to do things in C. But then when they try to code review - they lack even the most basic understanding of OOP design and dev. They focus more on the style of the code; spacing; method names; etc.
One of the senior level people say we should be writing our own logger instead of using log4j because of one negative review of log4j in an academic PDF written ages ago.
How do I deal with this? How can I explain to them that their design is faulty or that they are really behind the times, without coming across as a jerk. I've only been with this organization for about a year - so I don't know how much credibility I will have.
Regarding the code review, I would say make them happy. Name and space things the way they like. Focus your time on better design, of course, and enjoy the ADA reminiscing, it still can give you some background of where things are today and how they got there.
In other words, don't take that part too seriously. Worry about what is important to getting the job done. The job in this case is making those that matter feel you made a positive contribution to the project.
Regarding Log4j, I would just suggest a different framework. Either the built in JDK logging (can't complain about that, it is a built in API) or something like SLF, which lets you plug in whatever you want (including your own, I guess, which you can then throw away and replace with something real when they realize it was a mistake, and you only have to change the classpath).
Now there will be times where it is important. In that case, make it sound as much as possible that it is their idea. For example, on the logging, state that there are many logging frameworks out there that represent a lot of lines of code, and you were wondering if there are other ways to leverage that work for this project, and then let them "figure out" the solution.
There will be times when you have to push something as your idea - there will be no other way. In that case stick to the evidence, martial allies as much as possible by keeping relationships with those that do have influence in good standing, and realize that every battle you fight, you lose position, even if you win (perhaps especially if you win).
I'd recommend approaching your concerns as 'suggestions'. Make a suggestion and ask for their opinion on it, that way they feel as if they are still in control even though you've planted the seed and are directing the conversation.
Regardless of how long you have been with an organization, you are there and you are there for a reason (they hired you for your input). Find your voice and how to best approach your team members with suggestions and/or concerns. This is a crucial part of being a team member and will increase your value.
Get a good formatter and create you method names this which they cannot complain about then your discussion can move onto real issues.
Some people cannot get over these little details during reviews, so you need to make it a non-issue.
Your work has to gain credibility before they will listen to you. So yes, do as others have recommended, and make sure the unimportant formatting laws are adhered to. But also do such high quality work that they can't ignore or marginalize you. Try to guide them in ways that makes them think the ideas are coming from them.
I disagree with the recommendation of another logging framework besides log4j. Citing an old review, without any kind of personal experience, should not win the day here.
However, there might be a way to turn this to your advantage. If you agree and recommend the logging built into the JDK or Apache Commons logging, you'll find that both are quite similar and can actually use log4j as their underlying implementation.
If your adversary isn't paying much attention, you may win points for giving in and avoiding a bike shed argument and STILL get what you want.
Respect your elders I say! :)
Really though, just remember that a lot of these gray beards were probably programming while you were in diapers. That doesn't make them experts in the latest technologies, but it should at least earn your respect. And sometimes if you can find a way to look past all the hemming and hawing and "back in my day" stuff, you can pick up some pearls of wisdom from those old dogs!
Now from the programming perspective, looks like Yishai has it right. It should be pretty easy to conform to the coding styles they want, and once you've made them happy you can run with the code the way you want.
And if you have to present a counter opinion, back it up. If you want to use something like log4j, talk about SPECIFIC projects in your past where you've used it and it worked fine, and offer to help anyone get past any problems they have with it, etc. etc.
Remember, while you look at the old gray beards as not knowing how to do some cool new programming, they probably see you as a young whipper snappers with a lot of crazy ideas out to change the world. An ounce of patience will get you a pound of respect.
I am an old gray beard but I abandonded COBOL 35 years ago and code in dotNET C# and have kept up with the young wippersnappers and try to mentor them too. With that said I see a lot of managers and programmers that are still in the dark ages like VB6 and cannot accept web farms, web services some of these gray beards and young wippersnappers cannot normalize a database table to 3NF let alone code nTier, WCF or have a clue. Worse yet some of the managers are 30 years behind and rely on the VB6 at best and a flat file using Access97.