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advantages of play framework for people coming from php / ruby / python

One of the strongest selling points of play framework is it's development cycle, just fix the code, go back to your browse, hit reload, and go one, all without the write, compile, deploy, hassle typical of j2ee web development.
Nevertheless, for web developers coming from php, ruby or python this is hardly surprissing, moreover it's considered the natural way to develop web apps.
Moreover, many of the advantages of play, (efficient template system, resolve errors quickly, stateless, fun & productive) are taken for granted in those frameworks...
So I'd like to know what do you think are the main advatages that play framework brings to web developer coming from dynamic languages.

From my point of view these are the main advantages
it's java, so if you don't feel confortable with java, and you are not willing to learn it, that might not be an advantage. On the other hand, if you HAVE to use java, coming from php or rails you will feel right at home with play
it's static (except for templates and routes, that's about to change on the next version), so you have compiler checks and safe refactoring.
tool support: IDE support (eclipse, intellij, netbeans)
endless collection of libraries to do everything you want, well, it's just java
runs on the jvm, which has years of experience and optimizations
it's compiled, so you may expect better performance
it's really fullstack: it comes with everything you need to develop a web app, compiler, web server, in memory db server, offline documentation, integrated database manager, local and distributed cache management, fixtures, evolutions, dependency management, lots of utility libraries, unit tests, selenium tests, ide support. You need no apache or mysql setup to get up and running
it has advanced features, like asynchronous requests, web sockets, asynchronous jobs
zero development environment setup: just unzip play.zip, play new my app, play run myapp
excellent documentation
great and fast growing community
scala is firmly in it's horizon, if you come from a dynamic language you might feel more comfortable with a language like scala, even though it's static
can be deployed to any servlet container, like tomcat, but also comes with it's own lightweight server
it's got an ever growing collection of community contributed modules
it's cloud friendly, works on gae, heroku, playapps, cloudbee, dotcloud, etc... (see this question)
source code: this is one of it's main advantages, even though it's often neglected. The source code is pretty readable, understandable and not over engineered. Even without much java knowledge, it's possible to have a look at the code, understand it, and begin contributing to the project
In my particular case, coming from a php & classic asp background, play allowed me get a web application up and running while learning java at the same time. it really let me enjoy my transition from dynamic languages to java...
Play has some advantages compared to other dynamic web frameworks, but I think that if you are proficient in codeignter, rails, django, etc, and if you are not willing to benefit from java's (or scala) ecosystem, you should stick to what you know...

A similar debate has been running on Google Groups recently, but more specifically comparing Play and Ruby (on Rails). I have tried to collate some of the feedback the community has provided on this topic, rather than just give me personal view. Hopefully this will make for a more rounded answer!
statically types business logic layer (and using the new templating engine, even your views will be statically typed). This has therefore the advantage of better IDE support as well.
Can use Java as well as Scala, so you are not restricted to a single technology stack.
Play just works out of the box, but is also highly configurable, so does not force you to work in a particular method.
In memory DB. Great for new developers, who just want to get started. No need to go through setting up WAMP/LAMP server etc, just to get started. Just download play, and you are ready to go!
Its Java (or Scala)! I got hooked on Play because I used PHP begrudgingly because it was the easiest way to host a personal website, but hated that I was building software in a way that I did not feel was well structured. Play allowed me to use Java without the bulk of a J2EE application.

Play framework. Play is heavily inspired by Ruby on Rails and Django. A developer familiar with any of these frameworks will feel at home.
1) Play leverages the power of Java to build web applications,By lifting away the Java EE constraints, Play provides developers with an easy-to-develop and elegant stack aimed at productivity.
2) It focuses on developer productivity and targets RESTful architectures. Play is a perfect companion to agile software development.
3) Folder structure of the play mostly match with the Rails.
4) Play loads the code dynamically. Just fix the bug in Java file and hit reload, the change will get reflected instantly on webpage. No need to go through those sluggish rebuild / deployment / server restart.
5) No configuration: No configuration required just download, unpack and start development.
6) Error discovery is very easy, When an error occurs, play shows the error message, the file path, line number, and relevant code snippet right in the browser.

What exactly Java EE6 and do I have choice not to include some of features?

When I looked into Java EE6 doc and some other articles, Java EE6 is a platform.
To me, platform is just Java with bunch of API/framework available like JSF, JPA, Web services like REST. (more like bunch of jars maybe?)
So anyway I got Netbean6.9/Java EE6/GlassFish v3 bundle but figured I don't need JSF at all.
Is there a way to remove JSF from Java EE6 so that I can save some disc space on my server?
Sorry if my statement doesn't make sense because I'm not fully understand what exactly Java EE6 by reading documentation.. (or this JSF is bundled with Netbean6.9...)
Update:
I'm building REST web app so far using JAX-RS and JPA (toplink essential) and for UI side, JSF was going to be used but we decided not to, so wondering if things that won't get used can be removed. (after reading comments I think removing JSF is not good idea though)

Java EE is a set of interfaces/annotations/etc for performing tons of different kinds of tasks commonly needed when building, well, 'Enterprise' applications. (the definition of which is its own multipage thread.) Glassfish is includes an implementation for each of the different APIs that make up JavaEE. Basically, when you use Glassfish, you can just go ahead and use anything in a 'javax ' package and it will be there for you, working. (although sometimes not the most performant or scalable implementation available...)
There are several options for java web containers that don't include implementations of the entire J2EE API built in. Tomcat and Jetty are probably the two most popular and widely used. Tomcat installs and integrates right into netbeans very well. But if you find yourself wanting to use something in most javax packages, you will need to provide an implementation, include the jar files yourself, etc.
--
Also, as an aside, the very, very nice Glassfish administration console (which is to me the chief motivator for using Glassfish) is done in JSF, so no, you can't really remove it :)

Regarding JavaEE, you don't need any jar file, but only a compliant application server, Glassfish in your case. And no, you can't remove features you don't need. But you don't have to use them if you don't want to... ;-)

In order to be J2EE certified there are certain requirements that must be met, and removing some of the functionality may cause problems.
For a nice discussion on what it means to be certified, you can start with this:
http://en.wikipedia.org/wiki/Java_Platform,_Enterprise_Edition
A Java EE application server can
handle transactions, security,
scalability, concurrency and
management of the components that are
deployed to it, in order to enable
developers to concentrate more on the
business logic of the components
rather than on infrastructure and
integration tasks.
If you find that you don't want to use much of J2EE you can look at something like the Spring framework (http://www.springsource.org/) which will offer more capabilities than just tomcat/jetty, but you can add/remove the parts you don't need, though you will need to include the core.
If you just need JAX-WS for example, then you can just add that manually, but, depending on your application you may find that there are many parts you will eventually need to make your life easier.

Start with Java (JVM) ecosystem

I have came from another question to this one:
How can one start with Java (JVM) ecosystem? What are beginner, intermediate and advanced knowledge-bases (bags!)? To be honest Java ecosystem was always a bit confusing to me, so it would be very helpful to provide some "reference references" and "defacto tutorials" for learning (curve!) JVM.
Note: I want to use JVM with Scala (or Clojure) but not Java itself.
I am a C# developer (WPF, Windows Forms, ASP.NET, Web Services, ... like that).

The Java Tutorial is a good place to start.
Update: you have enough questions for about a dozen posts here ;-) Honestly, you should do some research yourself (Google is your friend), then ask more specific, targeted questions; that would yield better results. (e.g. I don't think anyone can answer your question regarding Swing or JavaFX without more specific details about what you are trying to achieve.) I try to give a few pointers below, about areas I know to some extent.
for servlets and other web frameworks, here is a bunch of tutorials.
Tomcat and Jetty are both application servers.
there are a lot of different web frameworks, because different people have differing preferences, ideas and style, so many have created their own framework. It can be confusing, but at least there is choice :-)
for persistence, apart from JDBC, ORM frameworks are another strong option. I use Hibernate and I can recommend it; in a bigger project it can make your life much easier. Ultimately it depends on your specific project and constraints; there is no single right choice.
AFAIK Java has no equivalent of LINQ.
See also this post for further recommendations.

Java based web applications need to run inside of a web container such as Jetty or Tomcat.
You build your app and deploy it to the container which hosts the application at runtime.
Pure/plain JDBC should only be used directly by simple applications or integration layers that do not have access to the class model.
Most applications that I have seen have used some kind of Object Relational Mapping framework which models the entities as classes at a higher level than plain old JDBC.
Popular O/R frameworks include:
hibernate
toplink
datanucleus
cayenne
For web based development, you could start with AppFuse, see the quickstart guide.
AppFuse is a templating system that generates the skeleton of an application for you.
Then look deeper into what has been generated, and see what frameworks they are using.
AppFuse lets you choose between different technology stacks, so you could compare.
I haven't seen AppFuse support for Guice or GWT.
Guice is a Dependency Injection framework, others that could be used instead are Spring or picocontainer.
Another investigative approach that you could try would be starting with AndroMDA, which is a model driven architecture framework - you start with a UML model and then generate or forward engineer a working application.
AndroMDA also lets you control the choice of the underlying framework implementations by configuring different cartridges, once again you should dig deeper to see what they are using in the generated application.

If you are looking for a basic introduction, then the Java Tutorials are nice. To do other things like Java Web Development, then your going to need to consult google for the respective technology since they vary so widely.
One book though that I highly recommend taking a look at is Java Concurrency in Practice

Yeah, it is almost impossible for new guys to get started. This is going to drive away a lot of developers, and Java is in danger of not having constant new bloods. The old farts would love that, it's great for career security, and that's why they are making Java more and more complicated.

Taking the next step with java development?

I want to take the next step in java web development, I am hoping to get insight & feedback on: what my next steps should be and how best to take them.
While learning the basics of java web development, I put together a simple web app that performs simple accounting and financial calculations. The web app is on a single jvm, uses Tomcat, and has standard web functionality - i.e. login/logout, basic security, etc.
How can I make this web app more "enterprise ready" - distribute functionality of tiers over different servers/jvms, HA, balance-able, etc.
What do I need to know/learn? - i.e. EJB3 or Spring Framework (seems spring is better option), REST and/or SOAP, etc.
How would one recommend (books, websites, etc.) I learn the "requirements" (see preceding line)?
Thanks!

In my opinion, you should try different approaches for a same problem, so you could compare the pros and cons of different tools and frameworks.
For instance, try to build an application using EJB, and then the same application using Spring. Take the presentation layer of your code written with JSF and then rewrite it using Tapestry.
I think this will be very helpful to you, as you'll be able to make best decisions when choosing tools for your future developments.

A few things to consider, as food for thought:
How good is the error handling/logging of the application? For example, if the user tries to put in X in for a currency value, what does the application do?
What is configurable within the application from the user and what is in configuration files and what is in a database with regards to configuration? Do you have passwords encrypted within the application?
What patterns would used in building this application? Are there patterns you could see using now that you have a prototype?
Is this application ready to handle different currencies and languages?
What happens if someone leaves the screen for a few hours and tries to use a form?
What administrative functionality does the application have?
Does it handle the case where the user has JavaScript disabled?
What are the limitations of your application, IOW what can't it handle the way it is?
Have you considered trying to write a manual for the application?

EJB or Spring? gets asked quite a lot nowadays, here's a decent related question about them.

Have some real users using your application. You'll be amazed on how many "new" features/improvements can be performed in your app ( and the technologies you'll learn to satisfy those requirements ) by having real users using it.

I would suggest the following books/tutorials are a must for every Java developer:
Manning: Spring in Action - 2nd edition
Manning: Java Persistence with Hibernate
Core JavaServer Faces
Adobe Flex ( Adobe website video tutorials )
Effective Java
Apart from the standard technologies above you must be familiar with
Different testing frameworks , JUnit is a must
Build tools like ANT and Maven
Also you can build small projects by downloading trial versions of MyEclipse or Flex Builder.

I suggest that you create small java experiment projects for each new framework/library that you want to learn.
I've had good success using maven to help me quickly and consistently create java projects that I use to experiment with one technology at a time, such as Spring, Hibernate, etc. I use maven's site life cycle to record notes about what I learned and to document how to build and run each project. So, now I have 20 or so projects that I can use as baseline projects, one for each framework, to build upon.
Also, I prefer buying and reading books rather than relying on google and websites to learn new frameworks. Seems that I'm able to learn a lot faster this way.
I also suggest that you write web apps that you, yourself, would want to use. Or write a web app that solves a problem you've been having. I've found that I learn a lot more this way rather than simply copying and pasting from examples in a text book.
Hope that helps,
- Dave

Spring or Tapestry would be good options for new learnings. Does your app use any web services? If not work those in. Work with other application servers like JBoss and Weblogic and note their nuances with java. I'd also recommend learning Maven and work that into your build/deploy process.
Have fun,
Mike

You could vastly reduce the time taken to build your apps by learning some Test-Driven Development.
Try learning JUnit - it's becoming a core skill now, even in unagile shops.
If you're focussing on the web, try out Selenium - which has a Java controller to drive your tests from Java test cases.
After investing a bit of time in TDD will pay off no matter which frameworks or apps you work on. If you learn to test drive your code, you'll end up with smaller, cleaner code and less debugging.

You might look at AppFuse, which is a bundle of Java things together.
Or, you might take a look at a few more technologies to play with and add in:
Version Control - SVN
Tools - Ant or Maven
Framework - Spring, Seam, Struts
ORM - Hibernate or iBatis
Test Driven Development - JUnit, Emma
Continuous Integration - Hudson
I'd also read the Pragmatic Programmer and/or Code Complete.

Allow me to state that "enterprise"-ready does not necessarily imply scale-out solutions, many, many enterprise Java applications are running on larger systems requiring long-running-systems skill of their own.
I recommend mastering the Java language and runtime, understanding how bytecodes and loading traverse the JVM vs. focus on any given framework.
Speaking of frameworks and if you really have the time, try recreating an application framework yourself. Try and re-invent the wheel. IMO it is an excellent lesson in why frameworks themselves exist and teaches one to employ the features instead of always trying to work around them.
One more thing, never forget the database. I don't care what that looks like Oracle, MySQL or NoSQL, but become also an equal master at the data store.

How do you go on about learning enterprise Java application servers?

Alright, the question might be broad. We've been looking at Jboss and a few other similar app. servers.
From the feature list it would be perfect for replacing our soon to be outdated homegrown reporting application on the server side. But at this point, for 2 developers, just grasping all the setup, configuration, administration, tuning,testing not to mention the APIs and programming itself just seems way too much, too big, too complex.
What path does people take to become familiar and productive with such application servers ?

Start with a simple one, and only use a more complex one if you really need the features.
For example, Do you really need the full JBoss stack? Would Tomcat not be sufficient? It's much less of a handful.

I would approach this the same way I approach anything new.
Start with the documentation - read the introduction and basic setup/configuration documents. Then move on to tutorials and maybe some simple apps that I find interesting. In your case, maybe port a few features over to the new system. As time goes on, you should get better with the tools at hand.

From my experience using one is the best way to learn what you like/dislike about it. Once you have a project set up for one application server it should not be too much work to migrate it to another. I am currently working on an application that we develop & test daily using a simple Tomcat v6 server, but which runs in production on both Websphere Application Server and JBoss.
As a side note for your development, I strongly recommend looking into integrating your Eclipse development environment with your chosen application server through server adapters - it will greatly speed up development tasks and simplify the debugging process.

I'd say that the minimum features for using Java EE are:
Servlets and JSPs, written using JSTL (no scriptlets)
JDBC
JNDI for pooling database connections (optional but recommended)
Basic authentication for security
You can accomplish a great deal knowing just those. If you want to minimize the learning curve, I'd recommend starting with those and staying away from EJBs, JMS, Struts, JSF, etc.
Another benefit is that this subset of features is common to both servlet/JSP engines, like Tomcat, Jetty, Resin, etc. and full-blown Java EE app servers like WebLogic, JBOSS, WebSphere, etc. An app that runs on one should be portable to any of the others, as long as you stay away from app engine-specific extensions.
You should realize that there's a trade-off here. You'll have to develop pieces that might be easier if you leverage the app server more. But hopefully you'll start with some simpler problems and work your way up once you're comfortable with the basics.
There's another approach: Hire an experienced guide to help you with training and mentoring for the first project. A six-month gig with a reputable consulting firm might get you started.
Last of all, I'd recommend Spring. It would also have a learning curve, but it's a good alternative to Java EE EJB development.