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Google App Engine - Go vs. Python recommendations? [closed]

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Closed 11 years ago.
I'm looking into writing my first application of Google App Engine. C# is my 'native' language, and so writing the app in Java would of course be most logical. BUT, I'm a geek and would like to take to opportunity to learn something new.
Therefore its a toss-up between Python and Go.
Do you have a strong preference based on experience (ideally in the context of writing on App Engine).
If you've come from C# (or another similar language), how was the transition?

The recently-released Go runtime for App Engine is labelled experimental for a reason: Both Go and Go-on-appengine are new and in a state of change.
If you want to experiment with Go and running Go apps in the cloud, go for it. If you want to write a production app on App Engine, use Python or Java.

This question is about as subjective as they come, but I'll bite anyway.
Python is easier to learn, has a much larger development community, is mature, and has a lot of third-party libraries available for you to integrate into your application. It's a winner for sure.
That said, Go is an extremely well-designed language. Far, far more so than Python. Go was specifically designed to allow you to catch most mistakes at compile time, while Python is almost legendary for its ability to mask your mistakes. Go code tends to be easier to maintain. Go is also dramatically more efficient than Python -- several times faster or even several orders of magnitude faster, depending on what you're doing.
Both languages are very powerful and very fast to write code in -- you can accomplish a lot in a short amount of space. But Go is unfinished and still in a state of flux, with core APIs still changing. It has a comparatively small developer base, and very few "real world" usage examples. Nonetheless, even this early in its development, it's already shown to be a compelling alternative with a clear use case.

I did a Python app for GAE recently and coming from C# I had no problems/was able to pick it up in a few days tinkering with the docs and playing with the SDK (I had some previous experience with python).
Python is pretty intuitive, it's imperative and OO, might require a slight change in thinking from C# but nothing revolutionary - using the interactive interpreter will allow you to pick it up in a day IMO.
Learning how to use the datastore and figuring out other GAE specific API's (blobstore, image, mail) will probably be more work (it's specifics like transactions/groups, consistency modes ...) but you can figure that stuff out as you go/when you need it in your app.
One thing to note - recently announced pricing scheme makes Python a bad choice on GAE ATM because it cannot handle requests currently and this leads to one "instance" per request. This is also true for Go ATM (as far as I know). JVM OTOH can handle ~20 simultaneous requests per instance if I remember the mailing list conversations correctly. And you will be paying per instance/hour. This makes JVM the most practical choice if you plan on publishing your application in the near future.
Also using JVM you could use Scala (a new/cool language) and a framework like Lift which should theoretically allow you to port your code/avoid lock-in (disclaimer : I say theoretically because I'm only starting out with Scala and have no practical experience with Lift).
So I would recommend to look around the mailing list and see what other people are saying about the recent changes.

Personally I would prefer Python because is much, much more mature than Go.
In the past, I learnt, the hard way, what are the risks of choosing a not-so-mature technology.
Warning, I am biased to recommend Python because I like it but you should also be careful because I heard many complains about how much support does Google put on Python-App-Engine. People are asking for years to upgrade Python support and nobody hears them.
These being said, probably Java would be a smarter choice, especially because you are used to C#.

Go is still experimental on the GAE - so maybe not the best platform to learn a new language. Python is definitely a good choice.
Considering a new language do not forget that by choosing Java you get the JVM which allows not only Java code but also oder languages like: Scala, Grails, Clojure, JRuby any many others.

Python is since long supported on GAE - lots of tested information, infrastructure, etc. Go is new to GAE.
I would decide more on the language level. Coming from C#, choosing Python you go a bit more "high-level", whereas choosing Go goes more into the "low-level" direction. More low-level control, but also more concern about that. Choose Python if your interest is on application development, and Go if it's more about systems development. One important aspect for me would be that Go has actor-style concurrency built in, though I don't know how well supported this on GAE will be.

Best dynamic language to pair with Java on a Java project

What is the best dynamic language to pair with Java on a large Java project?
We are considering using a dynamic language for tests, controllers, services. Some options are Groovy, JRuby or Jython. What are the pros and cons of each for this? Ideally we'd be able to call Java from the dynamic language as well as call the dynamic language from Java.
EDIT: If it helps, we're using Hibernate with PicoContainer and Webwork.
Thanks,
Alex

There are really three dynamic languages that offer a very seamless interop with Java - scala, groovy and clojure. From there, I'd ask your team which language they would rather work in or have them try a prototype in each language and see what they think.
If the team efficiency isn't important in the beginning, look to what problem each language attempts to solve:
Groovy is going to be very loose but natural to experienced Java developers and allows fast prototype development due to it's duck typing.
Scala is going to enable you to write DSLs making it a good for frameworks and tools where you want to solve the problem in a language more akin to how you would describe the problem.
Clojure is going to impose lisp's functional programming and immutable state concepts and could be a very natural fit for problems in AI, natural language processing, etc.
Finally, I've gone down the path of looking for the perfect language to base projects on and have found there is no perfect language. All of the languages I've mentioned above compile to native JVM byte code and are quite solid. Sometimes you just need to pick a language that might not be as cool as the others but gets you on the way to solving your problem.

I recommend Groovy, principally because it interoperates seamlessly with Java, and is almost a superset of Java, so very easy for a Java developer to learn. I have absolutely no evidence to support this, but based on hearsay, guesswork, and personal experience, I suspect the Groovy community is much larger than that of either JRuby or Jython.
Incidentally, Groovy++ is way too immature to consider for production use, in my opinion.

The answer is, of course, going to depend somewhat on matters of taste and flexibility. If there are folk who don't have experience with Ruby or Python then Groovy is going to have a syntax much closer to Java (in fact it is a superset of Java), and consequently be a much easier sell.
I can't really speak to JRuby as I haven't used it.
Groovy gives you probably the easiest interop with Java of the three you listed. It also has a very nice BDD library in EasyB which I like a lot. On the negative side I don't think the features or syntax of Groovy really hang together very well. It can kind of feel like a whole bunch of separate extensions to Java.
Jython is of course Python so the syntax is different, but also has all the consistency of Python. Interop is very good at the script level but at least used to be a bit awkward if you wanted to write pre-compiled classes in Jython that you call from Java. The other main pro over Groovy for me is that is that you have a real REPL to interact with the Java project.
I would also mention Clojure, the syntax is even more different but the Java interop is excellent, probably the best of all, and again you have a REPL. On the down-side if folk have trouble adjusting to Ruby or Python syntax then a Lisp is probably right out.

Clojure is probably the best dynamic language for controllers and services. (depending on what you mean with "services".
Scala and Groovy++ has the best java interop, but those are not dynamic (well in Groovy++ you decide for yourself what is typed.). Scala has the look and feel of a dynamic language. Scala has good testing frameworks http://www.scalatest.org/ and Specs and AKKA is very mature for services and also has Java APIs

I'd suggest going with Jython. The syntax is clean, and you get whatever additional power/conveniences that Python gives you.
For example, if you were to go with Groovy, you are basically limited to only what Java will give you. Jython would add the powers of Python to that as well.
If it helps any, I've used Jython with Hibernate, SOAP, Corba, and EJBs and it is much easier than doing the same with just plain Java.

From PHP to Java. Any advice? [closed]

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Closed 10 years ago.
I've been doing web application development for the last 3 years in PHP. I'm now on the verge to give Java a go. My last use of the language was nearly 8 years ago and was mostly academic.
I'm reasonably well acquainted with PHP's object model (version 5) and I have almost exclusively been coding in OO. I would now like to transport that experience and use it to develop in Java.
Where I'm coming from:
linux as a desktop and server
Vim/gVim + plugins as an editor
MySql for db
apache httpd
experience with a bunch of PHP frameworks, Zend+Doctrine being the ones I use most
What I've garnered so far about a move to Java:
I need an IDE: IntellijIDEA, NetBeans or Eclipse
I need to pick a development framework. Some recurrent names: Spring MVC, stripes, wicket.
Now I need some insight that could help make this transition smoother. But from the way people talk about it, Java seems to be an entirely new beast with its own ecosystem. It sounds as though moving to Ruby or Python would actually be easier, which is curious since, when I look at it, Java conceptually seems the closest to PHP, albeit stricter and precompiled.
As weird as this may sound, very few people have publicly documented their experience of such moves. I have searched google, amazon and stackoverflow for similar questions and the results leave to desire. I just can't believe that I would need to start the same as a newbie if I wanted to be productive as a web developer in Java fast.
Anybody is welcome to respond, but I somewhat think that people with some valuable experience in both languages would enrich this discussion the most.
What helped you get going quickly in Java?
What concepts are omnipresent in Java and absent from PHP and vice versa?
Some gotchas for PHP developers going Java.
How long before you felt the transition was complete?

I wouldn't try to learn an IDE at the same time as learning a language. An easier transition would be to stick to your shell and habitual text editor, and use the following shell-friendly tools:
ant, for organising your project, running automated test suites, incremental compiles
BeanShell for interactive testing, trying things out quickly
A quick trick: javap from the commandline will give method signatures for any class in the standard library. Similar to php -r but gives more information since Java is typed.
The online documentation for Java is precise, professional, and consistent in tone and format. Unlike in PHP where all of the functions are in one flat namespace, the standard libraries in Java are class hierarchies. You've got to know your way around that standard library, which means knowing hierarchies + responsibilities: for example you've got to know that java.util.List is a subinterface of java.util.Collection with the addition of a concept of ordered entries. With that information in your head, a google search for java.util.List will take you to the Javadoc for the class, and the Javadoc will tell you exact method signatures and link you to a selection of concrete implementations.
Some miscellaneous distinctions:
Strings are sequences of characters rather than sequences of bytes. Absolutely the right way of doing it.
Systems produce and consume streams (of bytes or characters) rather than byte buffers. For example, if you wanted to filter the output in PHP, a standard practice is to ask ob_get_contents for a byte buffer then to transform the whole buffer. In Java, you add a filter to your servlet that transforms the output a byte or a character at a time. It's a bit imposing to work with initially but it's simpler and more Lego-like when you get used to it - your stream processor doesn't have to know where things come from and where they go.
Almost everything useful is an interface, and creating an instance of an interface can be tricky, non-standardised, and not always well-documented. In PHP, you can get up and running with XML with new DOMDocument(). In Java, org.w3c.dom.Document is an interface, so new() won't work. Javadoc is very precise about how interface instances behave once they come into existence, but it can be quite coy and prudish when you're trying to find out how an object is actually born. Very often, you'll have to look for tutorials and code examples and copy-paste a piece of boilerplate that gives you an instance of DOMDocument or java.sql.Connection or whatever. One reason frameworks like Spring are popular is that they separate out the ugly object-creation code and present you with a world where interface implementations are just magically there.
I actually switched in the opposite direction. I found that Java works very well in a large company where you might be working on a single component, handing it off to someone else who integrates that component into a larger system, which is then packaged and handed off to a separate operations team - that's where all this indirection and configurability (FactoryBuilderFactory type abstractions, web.xml files, etc) makes sense and does something useful. In a small company where the programmers are the ops personnel, Java is a lot more work. With Java, you'll have to get used to concepts like starting up the Java process, monitoring the Java process to make sure it stays up, monitoring the Java process to make sure that it doesn't go into a coma where it's alive but not responding, shutting down and restarting the Java process with minimal disruption when you're updating code, etc, etc. If you have separate ops personnel, that's fine, it's their job, they're very good at it. If you're a programmer, babysitting a Java process can be distracting and difficult to do well.

Start with the Java Tutorial
http://java.sun.com/docs/books/tutorial/getStarted/index.html
Then go buy Head First Java
http://oreilly.com/catalog/9780596004651
It will get you going pretty quickly in the language which is essential regardless of what you want to do.

Strictly speaking, you don't need an IDE to work in Java. I've been coding heavily in Java for well over a decade (and heavily on other stuff for over 25 years), and I don't much like IDEs. Perhaps that implicit indicator of my age is part of the issue :-) It's a trade-off, like anything else.
I'll plug Stripes as a nice simple framework, but mostly that's because it's relatively small and limited in scope. The large frameworks like Spring are "kitchen sink" ecosystems, and learning Java with one of those frameworks may smooth some of the difficult parts but leave other basic aspects mysterious. Again, it's a matter of personal preference.
It's good to have somebody around who knows the language. Oh, and to that point, make a friend of the Java API documentation. As platforms go, the Java API has its ups and downs but for the most part the documentation is at least pretty thorough and pretty accurate.
You'll also want to get really familiar with JSP and its relationship to Java and Java web service architectures, because that'll be what you'll relate to your PHP experience most directly (I'd think).

The best move I made was from Java to PHP.
Beware of complexity. Primarily, the key to great software is simplicity, and that is why PHP combined with a good framework kills Java.
With Java, you risk becoming a slave to your servlet container and framework. Choose the simplest most flexible framework. Controls and custom tags are the devil. You'll waste days learning things that were designed to make development quicker, but are ultimately too complex and inflexible. Java will slow development due to: complexity, compilation, and static types. You'll come to loathe null pointer exceptions.
Edit: Tools aside, Java and PHP are very similarly structured "C" style languages. Much more so than Python or Ruby. It is the static typing and complex tools that make Java so foreign.

I recommend hitting up JavaBat at here
It will give you some good ideas. It took me 1 solid year in a professional setting to get a very firm grasp on Java and I have been able to move into other OO languages quite easily once I had the thoughts beaten into me.

This appears to be a bit of an old post, but hey...
I moved from C# to Java and I've just started a role and am moving from Java to PHP...
First off: Java is awesome :)
for your IDE get Eclipse, once you get used to it, you never have to leave the IDE (apart from SQL bits). It manages projects really well, you can download alsorts of plugins, such as SVN plugins. It allows you to run a Tomcat server within Eclipse and it will output errors straight to the Eclipse console.
for the framework, I used Struts and Tiles and Torque for the ORM, took me a while to get my head around them, but once we made friends, I can't imagine any other way of developing. Although I imagine for a small project it would be a lot of overhead!
agreed with an above post - get HEADFIRST JAVA, thats how I learnt and I used it for lots of other languages, they have a visual method of learning thats alot easier than pure textbooks - well for me anyway. I was up and running with in a day and confident within a couple of weeks I guess - but always learning :)
yip Java is strict, but you come to love it, for me moving to loose 'ol PHP is a bit wierd.
you will also need to download Tomcat to run your Java bits, its easy as to get running.
Java organises all your classes very nicely, none of this 'require_once(some_text_file.php)' rubbish, just 'import myClass' and off you go.
one of the things that annoys me is, there is no way of telling which JAR libraries you are NOT using, so after a couple of years working on a site, your lib folder can get a bit messy - specially if mulitple people are removing and adding functionality.
I could go on.
Paul

For my case, I only dealt with lot of procedural coding on the php, so jumping to Java, not only did I find everything to be more verbose and less forgiving than php (but now I know why it must be this way, and I love Java a lot) but learning to organizing my code in classes and also learning the eclipse IDE took about 1.5 years of just tinkering, trial & error, making stuff on my own (mainly swing applications).
I guess just creating stuff on your own, utilizing the vast amount of Java libraries out there to build your own stuff is fun is the fastest way. Also I think I could've saved more time by reading the java sun tutorials thoroughly. Even more time saving is making sure you've done a thorough search for libraries that prevent "reinventing the wheel".
Good luck!

Should I study Scala? [closed]

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.
Closed 10 years ago.
I am an experienced C++ programmer with average Python skills. The reasons I studied Python in the first place were:
to get a different perspective on programming (static vs dynamic, interpreted vs compiled, etc.)
to increase the breadth of projects that I can work on (Python allows me to do web development, develop for Symbian phones or knock up quick system administration scripts)
to complement my C++ skills.
I think that Python is great and I believe that I have achieved the above goals. I will continue to use it for small projects, scripts and web development.
I doubt that I can use it for medium to large projects though. While the dynamic typing is convenient, it allows a certain class of bugs that I find disturbing. Unit testing and linting can alleviate this problem, but static typing completely eliminates it.
After looking at some programming languages, I think that Scala looks like a good candidate:
I like the type inference and it runs on the JVM so it should be available wherever the JVM is available. I can also learn more about functional programming when using it.
But... I also have some doubts, and this is where I hope that the Stack Overflow community can help:
Portability: Linux and Windows at least I hope. What about mobile phones, is it possible to get it to run there?
C++ compatibility: can I mix C++ code with Scala? (JNI?)
Programming paradigm: I don't feel comfortable with switching to functional programming (FP) at this time. Can I use object oriented and procedural with some FP at first and then change the proportions as I learn?
Tool chain maturity: what's your experience with IDEs and debuggers? I'm using Eclipse right now and it seems OK.
Learning speed: considering my experience, how fast do you think that I can reach a workable level with Scala?
Deployment: how exactly do you deploy a Scala program? Is it a jar, is it an executable?
Finally, what do you think that are some of Scalas disadvantages?

Portability: Linux and Windows at least I hope. What about mobile phones, did anyone succeed in getting it to run there?
Yes. There is quite some movement about Scala on Android. As for J2ME, I saw something in that respect, but not much. There is some code pertaining to J2ME on the source code repository. I'm not sure how viable it is, but it looks to me that there isn't much demand for that.
I'll also mention that there is/was a pool on Scala-Lang about the desired target platforms, and J2ME was one of them, very low on the totem pole.
C++ compatibility: can I mix C++ code with Scala? (JNI?)
As well as you can mix C++ with Java, for whatever that is worth. If you haven't any experience with that, you can just read the Java resources, as anything in them will be applicable with Scala with no changes (aside Scala syntax).
Programming paradigm: I don't feel comfortable with switching to FP at this time. Can I use OO and procedural with some FP at first and then change the proportions as I learn?
Definitely, yes. Scala goes out of it's way to make sure you don't need to program in a functional style. This is the main criticism of Scala from functional folks, as a matter of fact: some do not consider a language functional unless it forces the programmer to write in functional style.
Anyway, you can go right on doing things your way. My bet, though, is that you'll pick up functional habits without even realizing they are functional.
Perhaps you can look at the Matrices series in my own blog about writing a Matrix class. Even though it looks like standard OO code, it is, in fact, very functional.
Tool chain maturity: what's your experience with IDEs and debuggers? I'm using Eclipse right now and it seems ok.
IDEA (IntelliJ), NetBeans and Eclipse all have good support for Scala. It seems IDEA's is the best, and NetBeans/Eclipse keep frog-jumping each other, though NetBeans has certainly been more stable than Eclipse of late. On the other hand, the support on Eclipse is taking a very promising route that should produce results in the next 6 months or so -- it's just that it's a bumping route. :-)
Some interesting signs of Scala tooling for these enviroments is the fact that the Eclipse plugin in development uses AOP to merge more seamlessly with the whole IDE, that the NetBeans plugin is being completely rewritten in Scala, and that there's a Scala Power Pack on IDEA that supports, among other things, translating Java code into Scala code.
The EMACS folks have extensive tools for Scala as well, and lots of smaller editors have support for it too. I'm very comfortable with jEdit's support for small programs and scripts, for instance.
There is also good Maven support -- in fact, the standard way to install Lift is to install maven, and then build a Lift archetype. That will pull in an appropriate Scala version. There's an scala:cc target that will do triggered recompilation as well.
Speaking of recompilation, neither Maven, and particularly nor Ant do a good job at identifying what needs to be recompiled. From that problem sprung SBT (Simple Build Tool), written in Scala, which solves that problem through the use of Scala compiler plugin. SBT uses the same project layout as Maven, as well as Maven/Ivy repositories, but project configurations are done in Scala code instead of XML -- with support for Maven/Ivy configuration files as well.
Learning speed: considering my experience, how fast do you think that I can reach a workable level with Scala?
Very fast. As a purely OO language, Scala already introduces some nice features, comparable to some stuff that's present in C++ but not Java, though they work in different fashion. In that respect, once you realize what such features are for and relate them to C++ stuff, you'll be much ahead of Java programmers, as you'll already know what to do with them.
Deployment: how exactly do you deploy a Scala program? Is it a jar, is it an executable?
The same thing as Java. You can deploy JARs, WARs, or any other of Java targets, because the scala compiler generate class files. In fact, you use Java's jar to generate a Scala's JAR file from the class files, and the Maven targets for Lift support building WAR files.
There is an alternative for script files, though. You can call "scala" to run Scala source code directly, similar to a Perl of Shell script. It can also be done on Windows. However, even with the use of a compilation daemon to speed up execution, start up times are slow enough that effective use of Scala in a heavy scripting environment needs something like Nailgun.
As for Scala's disadvantages, take a look at my answer (and other's) in this Stack Overflow question.

Scala is an evolving language well worth to invest in, especially if you are coming from Java world. Scala is widely covered at Artima. See this article from Bill Venners and also read about Twitter and Scala.
Regarding your questions:
Java can run wherever there is a JVM. No luck with the mobile phones however. You need a full JRE, not the subset that is available there.
This is possible with JNI. If something is possible with Java, then it is possible with Scala. Scala can call Java classes.
Functional programming is a strong point of Scala - you do need to learn it. However you could also start using it without taking full advantage of it and work your way with it.
There is a plug-in of Eclipse. It is not best, but it will do the job. More details here.
If you are experienced, I would say really fast. I recommend that you find a book to start with.
See this faq entry for deployment.

Programming paradigm: I don't feel comfortable with switching to FP at this time. Can I use OO and procedural with some FP at first and then change the proportions as I learn?
Scala has full support for imperative programming, writing programs with no FP elements in it is a breeze (however, FP is useful and worth learning anyway).
Learning speed: considering my experience, how fast do you think that I can reach a workable level with Scala?
Quickly. There is a number of interesting features in Scala that may be not familiar to people coming from a C++, Java environment, like for example some of the features of the typing system. Some argue that the fact that there is a lot to learn in Scala before you know all of it is a problem with the language; I disagree. The presence of those feature is an advantage of the language. The more features the merrier. After all, you don't have to use them all at once, just like you don't have to buy everything that is being sold in the store.

Learning speed: considering my experience, how fast do you think that I can reach a workable level with Scala?
I also come from a C++ background, one thing I noticed is that since you will write a lot less code as compared to C++ for a comparable task, your learning will be expedited as you will get more done in the same time period. This was the same phenomenon that I experienced with Ruby.

Actually - if I were you - I'd study programming paradigms instead of languages. Of course you have to study an example language to study the paradigm. Knowing the drawbacks & benefits of different paradigms enables you to view your problems from a different side and makes you a better programmer (even in the languages you already know).
Picking up a language of a paradigm already known is a relativly easy task if needed. Since Scala is FP (at least you mentioned it) and C++/Python is OOP, it's a good language for you, I'd say.

You should register for this course by the Creator of Scala himself.
https://www.coursera.org/course/progfun

James Strachan (productive Java open source developer, for those not in the loop) has an interesting discussion of Scala here, and why he feels it's a progression from Java (the langauge, not the platform).
Scala looks like it's gaining a lot of traction. I don't think it's a flash in the pan, and is currently on my list of languages to learn (partly for the functional aspect)

Here's an anecdotal evidence regarding learnability of Scala.
In our company, we got several interns from U.Waterloo. They were told to write in Scala; never saw it before.
They picked up Scala and Lift remarkably fast; now they are producing Scala code; it may be not perfect, but nobody's perfect.
So, the fact that a manager does not know Scala may be not the best argument when you decide on adoption.

What are the benefits of Java? [closed]

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Closed 10 years ago.
I always hear that programmers try to pick the right tool for the job. I've never programmed in Java, so I was wondering What are its benefits? Why is it so popular? What should I use it for?
I just program recreationally. Is there anything about it that makes it particularly fun??

I think after 12 years or so, the "write once, run anywhere" mantra is almost true. Writing Java code pretty much isolates you from the platform dependent aspects of the systems on which you deploy it.

Portability
Incredible breadth of libraries
Bottom-up security
Performance
Robustness

Massive communities, the amount of help, libraries, IDE's, is huge (and thats a good thing).

For a casual programmer Java can teach a lot about object-oriented programming, and encourage good programming habits in general, without the need to worry about as many of the "messy" details (pointers, memory management) as, say, C++.
It's also a bit easier to debug "catastrophic" errors.

Java is really good at integration - there are specifications and implementations for integrating with many kinds of systems that you're likely to run into in an "enterprise" environment.
It's not really a "fun" language relative to popular high-level languages.

This seems to be getting healthy answers, but you might also want to look at "Why do people use Java?"

Java is a good language, but that is secondary to the importance of the standard library that comes with it. The jdk may not be the most elegant kit ever built, but it is extensive, powerful and reliable. Programming in Java the language is simple. Programming with appropriate reuse of the jdk is what it is all about.

Cross platform is in my opinion the most relevant benefit.
The main goal of Java was to create a programming language that could run anywhere. The target was GUI apps. This however never happen because the environment was too slow at the beginning ( now it has been improved ) but it prove true in the server side where the cost of development reduced a lot because the product development can be done in PCs and the deployment in very expensive hardware.
It brought easy of development also, because it was designed to have C++ like syntax but running on a virtual platform to avoid platform specific code. At first the penalty was the execution speed, because it was interpreted, but release after release the interpreters became more and more faster that even MS model its next generation of development after java and call it .net
Additionally You can have a read of the Java design goals here

I want to add one point: Java keeps a good compatibility to earlier versions. That means, your Java-projects are compile and run in most cases without any problem on newer versions. That seems to be a little point, but this stability in API's and language helps to build a big community around Java, including good tool-support.
Others already mentioned other important points:
good portability
lot's of libraries for nearly anything
easy debugging and easy to catch problems

There are only two reasons to use Java:
The Java Virtual Machine (Hotspot).
The huge amount of available libraries and tools.
There are other languages that run on the JVM and make better use of Java libraries than Java does, however.

After using Java for some time, I've come to the conclusion that it's fun to write in, limited in some very irritating ways, and it's performance is good though it seems that many programs are crippled by poor design.
I'm not sure if the latter is a function of Java, or an effect of Java.
In either case, in addition to all of the above stated benefits it's very useful for doing "net" related things. Treating resources with a simplified interface regardless of "where" the particular resource is, etc...
It is by no means a universal hammer.

oop provides like encypsilation ,inheritance,polymorphism not available in traditional programing .oop is closer to real life presentation of the programming
1. Relation ships can be representation using inheritance
2. Programme developement become easy due to increased modularity