The Mutable State-of-Art

Once very often, social media lights up with opinions about the Javascript language, frameworks and its ecosystem being terrible. Some time ago, there was one around React framework, and the question was whether putting all HTML/CSS/JavaScript in one file is a really a good thing, which is against the age old practice of separation of these technologies.

Whenever people question the new ways of doing things, I am reminded of one of the greatest quotes by the Sanskrit poet Kalidasa (4th century CE).

“Just because its old, something cannot be assumed right. Just because its new, something can’t be brushed away. The smart ones analyze and adapt, the fools are swayed by others’ opinions”.

Many retweets, faves, dislikes, epics, savages later, the question still remains: What is the right language or framework?

The separation of technologies then, say 15 years ago, was not intentional. It was a necessity of times. CSS, HTML, JS were advancing independently, performance in browsers were so poor and finding an engineer who could do all was almost impossible. But now, we still have specialists designers and developers, but in general they have a good idea about the other technologies. I still remember back in my IBM days, pointing out to JSP structures to our designer, on where to make style changes. But now these frameworks and their idiosyncrasies are not strange to designers.

Here are my thoughts on why it is pointless criticizing the Javascript world for its organic growth, and equally pointless to criticize the criticism.

Whether “language purists” like it or not, Javascript is ubiquitous. Yes, that’s very hard to digest. Despite its “severe short comings”, it has conquered the net. Why? As IT engineers, we keep holding ourselves to this arbitrary sense of “perfection” and trying to judge everything against it. Typed languages, OO Patterns, Functional paradigms, Modularity, Testability – we seem to know what should be “right” and we are inching towards it – but we just aren’t there yet, we say. But we will know when we reach it, we say. Really? Every language invented since Javascript, seems to be solving the same problem of types, patterns, modularity, dependency etc, only in different syntax combinations.

Here is a fundamental question: Have we got anything right at all in the programming industry at the first stab? Or is 50 years too short to judge? The real limit of the problem is that physiologically, human brains can only process a limited amount of information, so it has to break complex into simple pieces. Eventually the simple pieces evolve to become complex enough, or perhaps our brains shrink so it perceives simple things as complex. So they have to be broken again. But the broken simple pieces have something in common with previously broken simpler pieces that they have to re-integrated. Thus we swing into an eternal pendulum of centralization and distribution.

Here is an illustration with evolution of Java, but you can substitute it with any starter technology:

  1. Java and JVM were originally built for small devices
  2. But once it entered application server space, EJBs were added to tackle distributed environments.
  3. EJBs became so complex, it was abandoned and broken into smaller pieces
  4. Smaller pieces were dependency-injected to form a bigger solution, but eventually they grouped into micro services
  5. Micro-services combined with distributed systems to facilitate container architectures, like Docker
  6. Container architectures are becoming complex and are yielding to orchestration solutions like Swarm and Kubernetes
  7. Predictably, By induction, orchestration solutions will become complex and will yield to Local Clouds
  8. Predictably, commodity local clouds will be broken into Fogs, Cirrus, Altostratus, Cumulus … and delivered by drones.
  9. Predictably, Drones functionality will super-evolve, so they will eventually need a new programming language specifically written for small devices… well…

Much like a fractal, as we dissolve complex problems into simple solutions, they just take a new shape of complexity, due to external influences (mobile, bandwidth for eg). The point is – This cycle will never end.

Working as a Web + Network application engineer (on the SDN controller OpenDaylight) I am seeing two ends (philosophically speaking, they are the ends and the means respectively) of a spectrum. Both UI and Network are always evolving in interesting ways, yet we can analyze these two into a fundamental problem statement:

Network: Deliver content (a packet) from one place to another place, efficiently.
UI: Deliver content (html) from one place to another place, for a user friendly read.

(Of course I am intentionally oversimplifying, but as an end user, when your bandwidth drops below 1Mbps, you call up the customer service to negotiate a discount, not enquire the complexity of the network protocols).

But just to solve the packet delivery problem, think about myriads of protocols and schemes created – TCP/IP, VLAN, MPLS, BGP, VXLAN, OpenFlow, NETCONF and many combinations of these. Similarly in the UI world, all we have to do is deliver readable content, but there are so many aspects and choose-your-noun libraries CSS, SASS, WebPack, D3, Material, visualization, accessibility, modularity, layouts and the most subjective of all – Colors!

So why do front-end developers keep seeking and preferring newer frameworks? There are many reasons and not all are technical. The fundamental reason is: Boredom. Human mind always seeks something new. Not because its useful, but it has to be something just different. And perhaps have a personality.

For any framework in general, to be popular and become sustaining, it should satisfy ALL these conditions:

  1. A very nice familiar sounding easy-to-pronounce name
  2. Should NOT be one person driven
  3. Code should be easy to change and testable
  4. Good documentation
  5. Not do too much magic
  6. Ability to teach it easily to others

The golden rule of framework success is this: It takes a few smart developers to create an idea. It takes a few hundred average developers to sustain it, because the smart developers have moved on to a new idea.


ReactJS Gotchas #001

Tags: Mocha, Chai, Sinon, React 0.13.3

Problem Context: Run a unit test using Mocha against a Form.

Error: Invariant Violation: addComponentAsRefTo(…): Only a ReactOwner can have refs. This usually means that you’re trying to add a ref to a component that doesn’t have an owner (that is, was not created inside of another component’s `render` method). Try rendering this component inside of a new top-level component which will hold the ref.


beforeEach(function () {
rendered = TestUtils.renderIntoDocument(
<MyComponent ref="myComponentRef" param="10" />


Don’t use ref attribute for the component when running a unit test (ie remove ref=”myComponentRef”)

React Impressions

Let me start with a mandatory statement that many first-use-React-blogs start with: “I have played a bit with React and its great. And…”

Having recently completed a decent sized project in ReactJS, I have to say, once in a while there comes a library or framework that truly makes you go back to the basics and think. Despite much gained knowledge, it is fascinating to see that human brain collectively misses the fundamentals as “progress” happens. Much like an experienced cricketer suddenly losing ‘form’ and is adviced to go back to basics. It is not that he forgot to how hold his bat, but that intuitive coordination or that ‘elegant touch’ has disappeared. Perhaps we humans are not wired to over-learn! From simple to complicated to simple, we keep oscillating, just like we keep regurgitating the centralized and distributed system concepts.

It also emphasizes two underestimated facts in software engineering:

1. Creating good software is hard
2. Keeping it simple is even harder

I still remember Rod Johnson’s impacting book ‘Java without EJB’, (I was advocating the same in one of my early projects – removing all EJBs because its complexity did not make sense and the book gave me a lot of cannon). Spring framework made a great impact on many web developers then, bringing in IoC principles into a Java container. (Spring wasnt the first one though, PicoContainer was).

Facebook’s ReactJS is one such framework going back to basics. Apart from the usually quoted strong features like VirtualDom, simple lifecycle model and one-way data flow, what is it that really made React tick? After all component based frameworks are not new – Awt/Swing, Tapestry, Vaadin, GWT, JSF/Seam, Wicket (all Java based) and several Javascript-based were successful – but they all fell into the trap of hiding the complexity of Javascript (and to some extent HTML/CSS) from the developer and that turned out to be a costly decision. Everytime Javascript and HTML standards evolve or browsers support something new, these frameworks have to undergo quite a bit of refactoring. Remember, both designers and front-end developers ultimately like to nano-control the HTML output.

Among the existing component frameworks, the gap between the ‘framework’ and Javascript/HTML is shortest in React. Compared to many frameworks that advocate a structure like .html,.js and .css for each component, React neatly rolls them all into one testable unit, surrounding it with a simple lifecycle. And with the virtual-dom concept, you can apply same concepts to mobile or even desktop apps.

Some complain that JSX is ugly. I first thought same, (I am not a big fan of XML based structures), but it took me all of 10 minutes to overcome it. In fact, I think its one of the smarter things that has come out of React: making Javascript expressions look like HTML. It is quicker to learn JSX than yet another templating language. Passing properties and reading state just feels syntactically familiar.

Another common complaint about JSX is that it makes if conditions and for-each syntactically harder, compared to say AngularJS ng:if/ng:repeat or Handlebar-type syntaxes.

<span ng-if={showElement}>I am here!</span>;


return (
showElement ? <span>I am here!</span> : undefined;

While the JSX version does not look concise, the ‘if’ and ‘for/map’ are natural and readable in programmatic syntax than in declarative syntax. Not only that, it can be elevated to a function to make the component reusable. And then it also provides an incentive to make the function stateless – so the component is now slowly turning into a dumb component. AngularJS, though concise, feels more XML-ly than React and you cannot reuse the <span> element as-is in some other place or context (unless you elevate it to a directive). The JSX downside appears to be that you keep creating component wrappers, but isn’t that problem to solve – making composability easier?

The biggest advantage of such componentization is, it also makes unit testing much more delightful. In our project, we use Mocha+Chai+Sinon, which seem to work pretty well. In React, you start to think in terms of composability, than just a page. Many a time, we wrote a complex component, but quickly dissolved/abstracted it into dumb components, by breaking out its props and state.

That’s another thing about React – the learning curve and refactoring is comparitively less steep than others, with only a few concepts to learn.

I am also often asked how long will this framework last? Will Polymers and Web Components take over the browsers? Unfortunately, the Delorean only went upto 2015 and the Almanac probably did not mention React.

His Last Framework

Its been a while since I visited my pyschiatrist and now, Chiropractor Dr. Pear – Perspective Readjustment Specialist. Last time, he helped me cope up an aggressive experience with pair programming. The front-desk handed me a big chunk of forms to fill up my software history.

Years of experiencing web frameworks: About 18.
First framework of pain: JSP Model 2, perhaps Applet, can’t remember.
Latest framework of pain: AngularJS
History of major pain points: EJB, WebSphere, WebLogic, Spring, Fusion Middleware, Wicket, ASP.Net Web/MVC, SharePoint, Grails, SpringBoot, Backbone, Ember, AngularJS and innumerable minor ones.
What type of pain is this? (Select one: Sharp, Shooting, Numb): All of them
Approximate location of pain: Initially Back-end. Then moved to Front-end.
Exact location of pain: Depends on Mood.
Frequency of occurrence of major pain: About every 18 months.

I physically submitted the forms and started checking my tweet feed. New tweets from dzone on Top 20 Javascript frameworks; AngularJS Jobs; Best 35 CSS Frameworks; Top 15 build tools for Javascript; AngularJS vs.., no wonder I needed a therapy.

The nurse called me in and after the initial handshake of pulses and vital stats, she said 200. I was idly looking at the magazines – PlayWeb, Maximum Frameworks… Dr. Pear entered after a knock.

Dr. Pear (browsing thru my history rather than looking at me): Oh, Hello! Its been a while from your last visit.
Me: Yes, Doctor.
Dr. Pear: And what brings you here?
Me: Well, Ive been spinning my head with the next web application framework and I haven’t been able to decide quite…
Dr. Pear: Well, the short answer is “As a consultant you should learn all of them !”, ha ha ha… (after a pause) Yeah, yeah I know. Its the viral season of frameworks. The Javascriptarix flu shot we gave last month was really a placebo. So what kind of framework you are really looking for?
Me: (a bit hesitantly) Not sure, Ive been taking the Javascript MVC Kool-aid for the last couple of years, but it looks like the pain isn’t gone…
Dr. Pear looked at me a bit condescendingly and said “MVC eh? in Javascript? Didn’t you get high enough on it in the Java/.Net world?”.
Me: Well, the Java web frameworks are kinda relegated to providing data services these days…

I had not finished. It must have triggered a raw nerve in him and he went on to a mini lecture of sorts.

“You see, web frameworks come in two general flavors – MVC and Component. Java failingly flirted with the Applet component model initially, and then took a stab at MVC via JSP Model 2, while ASP.Net took the component route after its success with Visual Basic. Interestingly, Java increasingly adapted the component framework model, but Microsoft abandoned ASP.Net Web in favor of ASP.Net MVC. Java/JVM probably tasted all kinds of frameworks in many levels – MVC (Struts, Stripes, Spring, Grails, Play) and Component oriented (Seam, Tapestry, JSF & Co, Wicket, GWT). The fundamental problem with MVC is – it sprays your logic and model everywhere. Many developers struggle to organize it between “what-they-are” vs “what-they-do”. As the complexity increases, the code gets re-organized by features, each of which in turn have the m-v-and-c. Add on top of that, the domain models and view-models are usually different, the whole thing about models start looking like a beauty pageant.”

He paused a second, probably aiming for me to get the pun.

“Component frameworks couple model and view tightly, because a view makes no sense without a model. But the biggest problem for them came from somewhere else: Javascript. Many pure java web frameworks are relatively stable, because of a stable and backward-compatible Servlet API. But component frameworks relied too much on encapsulating Javascript and HTML and in JS world, Friday’s release is outdated by next day Matinee show. Ajax, jQuery and related libraries innovated way too fast and library encapsulation really made no sense. When the JS libraries went unsupported, it dragged the Java frameworks along. With NodeJs, NPM-modules and unit-testing frameworks offering a vastly superior build ecosystem, life became miserable for frontend developers, bogged down by verbosity and slowness of JVM build tools.”

Me: Well, that’s exactly why I am here for. What is the JS framework you would really recommend?
Dr. Pear: Of course Backbone. I love backbones, especially if they aren’t straight. Get it? Ha ha !

He realized I didn’t look at him very admiringly. He continued.

Dr. Pear: Ok. Well, I hate to say it depends, because you didn’t pay me to hear that. So let me tell you something else. With JS frameworks like Backbone, Knockout and Ember becoming first class citizens, server-side slowly mellowed down to doing CRUDGE-work (Create, Read, Update, Delete, Gather and throw Exceptions), now gloriously termed as Microservices Architecture. With AngularJS offering a complete MVC stack, it doesn’t make sense to write Views in server-side anymore.”

Me: So should I still stick with AngularJS MVW ? Besides its barrage of new vocabulary redefinitions like service, factory, provider, scope, directive, the next version 2.0 promises to be completely different and backward incompatible…
Dr. Pear: Yeah, I heard that. It appears that you really need to work on your persuasion skills on convincing your team about writing in new framework every year.
Me: (I looked at him awkwardly, wondering what to say)
Dr. Pear: (Ignoring my awkward pause) Well, the web has to evolve. Why do you think Javascript is going bonkers with frameworks – they have to compete with rapidly advancing browser features, handheld and wearable devices. Who knows, Javascript could be running inside your brain tomorrow. Ok, so you are now tired of MVC in Javascript world also. What about Facebook ReactJS?
Me: ReactJS. Yes I’ve heard of it. Isn’t that a component oriented JS framework?
Dr. Pear: It sure is. You write HTML directly within Javascript or CoffeeScript or Typescript in an XML like syntax and compile them to Javascript.
Me: Im not sure I like the sound of that. Thats not even the best practice.
Dr. Pear: Well, its time to Refactor the Best Practices too. IMO, ReactJS may indeed work out well, because unlike the Java component frameworks, its closer to Javascript, it uses Virtual DOM providing fantastic rendering speeds and helps write isomorphic apps. If you get used to JSX, you will love it.
Me: What about Services?
Dr. Pear: Use one of the many flavors of Flux, Reflux, Fluxxor, Alt – the Action oriented one-way-data-flow-store.
Me: Hmm, that eerily reminds me of Struts. So, there is no really a best framework?
Dr. Pear: There is one – come up with your own. You will surely get a few fans.
Me: What if I get bored and jump ship to another framework? What about the developers who depend on my framework?

“Send them to me!” Dr. Pear said calmly, washing his hands for no reason. “If anyone thinks JS frameworks have more than 18 months of fame, they need a Perspective Readjustment”.

As I was leaving, he gave a parting shot, “Just remember one thing, if it makes you feel any better: no matter which framework, you are solving only a single problem: Delivering html to a browser. And by the way, if you haven’t selected your styling framework, I am open on Saturday afternoon”.

“Er.. Thanks, I will think about it”, I said as I flipped my phone to follow @ReactJS feed on my twitter.

As I was walking out I could see him frantically typing on the screen “Successfully readjusted for component framework. Will likely come here in the next 12 months looking for Web Component and Polymer adjustment.”

Note: Title is a tribute to AC Doyle’s His Last Bow.

Defining React Routers via API

One of the issues I faced while using React for my project is which Router to use? React obviously being a new framework on the block, there are plenty of plugins/components that are being actively developed and not many are (yet) stable. Some plugins are just enough different for you to want a new feature, but it wont support other features required. You can see how bullet-point engineering does not help much. You gotta try out a few and see what works best.

For the Router, react-router is the most popular, featured and well-documented, but it (v0.12.0) did not have one feature I was looking for: Ability to define routers closest to the handler itself.

All the routes go into a single file, usually your app.js, like this:

var routes = (
  <Route name="app" path="/" handler={App}>
    <Route name="login" path="/login" handler={Login}/>
    <Route name="logout" path="/logout" handler={Logout}/>
    <Route name="page1" path="/page1" handler={Page1}/>
    <Route name="page2" path="/page2" handler={Page2}/>
    <DefaultRoute handler={Login}/>
);, function(Handler) {
  React.render(<Handler/>, document.body);

If the application grows, this is less than ideal and can bloat the app.js. And it somewhat breaks modularity too (even though the app.js will eventually know everything, it forces you to wire the routes statically). The react-mini-router defines the routes as part of component as a mixin and I think thats pretty convenient.

With react-router v0.12.2+ the routes can be configured via api. This is not documented yet officially, afaik.


module.exports = Router.createRoute({ name: "app", path: "/", handler: App});


var AppRoute = require('./approute.js');
Router.createRoute({ name: "login", path: "/login", parentRoute: AppRoute, handler: Login});
Router.createRoute({ name: "logout", path: "/logout", parentRoute: AppRoute, handler: Logout});


var AppRoute = require('./approute.js');
Router.createRoute({ name: "page1", path: "/page1", parentRoute: AppRoute, handler: Page1});


var AppRoute = require('./approute.js');
Router.createDefaultRoute({parentRoute: AppRoute, handler: Login});[ AppRoute ], function (Handler) {
  React.render(<Handler/>, document.body);

Notice how the variable routes is replaced with [ AppRoute ]. This is important!.

In auth.js, if defining multiple routes, If you dont want to use parentRoute property, you can also do this:

AppRoute.addRoutes([ LoginRoute, LogoutRoute ]);

AngularJS – Startup time environment configuration

Starting to learn a web framework, doesn’t matter which platform – Spring, AngularJS, Grails, Rails etc. is easy. But once you go past the elementary-school level status, a question always looms – how to accomplish tasks the framework-way versus the non-framework way?

A seemingly simple stuff like configuring environment properties at runtime (startup), took me through internals of AngularJS. For server-side folks, the technique is pretty standard: use any of .properties, .xml, .yaml and then apply a built-in framework feature. For eg. in Spring, you can using the @ConfigureProperties, for Grails, use the Config.groovy and the framework will automatically place it in grailsApplication, similar to what Rails does. But how do you do it for a purely client side application (ie ‘static’ site, that relies only on rest calls from some other server)?

AngularJS allows a Module.constant() method, where you can just specify a Javascript object and DI-it where-ever you want. Neat. But often the config values are environment specific. One of the very nice solutions is to use grunt-replace and simply provide the environment specific json at build time and grunt replaces the config values for that build. One may argue that this is the correct way to do, because it provides consistency and tracebality in CI.

But in some cases the values may not be known ahead before build and is known only at application startup. So the question is what is the AngularJS way of loading the configuration file at startup? Would have been nice to have AngularJs look for a config.json properties file at root and automatically load and inject it into a variable like $env.

Obviously, AngularJS offers so much stuff – constant, value, service, factory, provider. I thought I need to stick the $http somewhere and load the config.json file and set it to AngularJS constant or value. Then inject the constant to any controller or service.

1. Inject $http into Module.constant()

Will not work, constant accepts only an object and not services. At this point of time, it is useful to get familiar with config and run phases of AngularJS. This stackoverflow question explains succinctly.

2. Inject $http into Module.config()

Will not work. You cannot inject a AngularJS service into config. You can inject only a provider into config.

var envconfig = angular.module('envconfig', []);

envconfig.config(['$http', function($http) {
var envConfig = {
restUrl: 'http://localhost:8080/rest/api/'

$http.get('/config.json').onSuccess(function(data) {
envConfig = data;

So, how about injecting a provider into config, and let the provider use the $http ?

3. Inject $http into the provider

Will not work. You cannot inject a service ($http) directly into a provider, like this:

envconfig.provider('EnvConfig', function($http) {

Though you can use a service within the provider, like this:

envconfig.provider('EnvConfig', function() {
var envConfig = {
restUrl: 'http://localhost:8080/rest/api/'

var loadConfig = ['$http', function($http) {
$http.get('/config.json').success(function(data) {
envConfig = data;
return envConfig;

//This $get, is kinda confusing - it does not return the provider, but it returns the "service".
//In our case, the "service" is the environment configuration object
//The $get is called automatically when AngularJS encounters a DI.
this.$get = loadConfig;

If you want to further configure the Provider, you can do this. Notice that the “Provider” suffix must be appended EnvConfig.

envconfig.config(['EnvConfigProvider', function(EnvConfigProvider) {
//Do something with EnvConfigProvider

While this almost works, there is a problem: $http is an asynchronous call, so its not guaranteed that the data will be returned with the values read from the config.json. Very likely the local envConfig will be returned always.

To get around you have to make $http a sync call, which is not possible. So we go deeper into the underlying framework of AngularJS – jQuery.

4. Load config.json synchronously

In the provider, you can do the following:

envconfig.provider("EnvConfig", function() {
this.$get = function() {
var q = jQuery.ajax({
type: 'GET', url: '/config.json', cache: false, async: false, contentType: 'application/json', dataType: 'json'
if (q.status === 200) {
angular.extend(envConfig, angular.fromJson(q.responseText));
return envConfig;

Notice, that the q.responseText is a string and is converted to Json object using angular.fromJson(). Also by using angular.extend, you can merge the local envConfig with the target one – this allows you to keep some default values that you dont want to immediately expose.

5. How about profiles?

If you have multiple profiles in the config.json, you can simply use the following technique:

this.$get = ['$location', function($location) {
var profile = $ || 'default';
var q = jQuery.ajax({
type: 'GET', url: '/config.json', cache: false, async: false, contentType: 'application/json', dataType: 'json'
if (q.status === 200) {
angular.extend(envConfig, angular.fromJson(q.responseText)[profile]);

return envConfig;

And your config.json is like:

  "development": { "restUrl" : "http://devserver/rest/api" },
  "qa": { "restUrl" : "http://qaserver/rest/api" }

And then call your url as http://localhost:9000/index.html?profile=development

While adding profile query string may not be recommended for production, if you are testing your UI against several backend instances, this might just help.

Thoughts on SpringBoot

In its new avatar, Spring enters the opinionated frameworks marketspace, and finally takes the Sinatra/Scalatra/Ratpack/Dropwizard/Spark route, where embedded containers (ie no external server containers) will start dictating the future. Whats an opinionated framework anyway? Aint all frameworks opinionated? To me every piece of code is just as opinionated as the developer who wrote it. Here are my observations about SpringBoot, after having worked with it for about 6 weeks.

1. Build support for gradle (+)
SpringBoot apps can be built using both maven and gradle. But I believe Gradle will eventually dominate the world of buildscripts. So the sooner your team moves to gradle, better will be your quality of this life and perhaps, next life too. Are you listening, .Net?

2. Starter poms (+)
Remember your 500 line pom.xml, where the tag <dependency> occurs 25000 times? Say good bye and start using starter-poms. Combined with gradle, a typical build file is now about 30 lines.

3. Configurations (+/-)
Spring is among the last standing action heros of xml-based application configuration in jvm world. Super hit when introduced, but soon became a liability. Thankfully, many developers challenged the xml tag soup and created innovative web frameworks (Wicket, Play etc.). Those who work with the Spring-based framework Grails, may have not touched an xml for a good period of time. If Spring MVC developers are still stuck with Spring without adapting Grails, I fail to understand why (well except for business impositions).

Ironically, SpringBoot seems to have many opinions when it comes to configuration – it supports 3 flavors of bean configurations: xml, annotation and groovy dsl. Having worked with Grails and other non-xml based applications for the last few years, picking up SpringBoot was bit of a chore. Grails autowires beans by name, and when custom beans are required, there is this wonderful bean builder. For me, java annotations are no better than xml configuration. Xml configuration proliferates verbosity but annotations defeat the purpose of wiring objects separate from code. While it brings type-safety, it also lets you mix code, configuration and logic and I think its a total mess. Annotations are like antibiotics – good in small doses (@ToString, @RestController, @AutoClone etc.), too many side-effects with overdose – building whole applications using annotations is @NotMyStyleOfTea.

A typical SpringBoot application has many many annotations – @EnableAutoConfiguration, @Configuration, @ComponentScan, @Conditional etc. Sometimes you end up with more annotations than the code itself and its not intuitive which is doing what when how. SpringBoot is certainly simpler for developers from xml background, but to me as a Grails developer, annotations have been a bit intimidating and sprawling. I don’t see CoC (Convention-over-Configuration), instead I see CoC (Configuration-over-Code).

Thankfully, SpringBoot has great (although not 1:1 xml equivalent) support for groovy beans dsl (via the GroovyBeanDefinitionReader). Groovy dsl is elegant, concise, intuitve and very readable. For some loss of type-safety (which could have been compensated by good tooling support), it comes with a great punch – wiring beans, environmental configurations, programmatic startup logic (as opposed to declarative) etc. I feel Spring can standardize groovy bean as the only configuration mechanism and shed all the fat of xmls and annotations. It would make the framework pretty lean and competitive in the already crowding lean frameworks market. May be thats what grails-boot is?

4. Properties (+/-)
Just like configurations, there are a few ways of defining and injecting properties. Coming from Grails background, the many ways of injecting properties was a bit confusing. SpringBoot supports both .properties and .yaml files. AutoConfiguration uses many default values for properties, but there is no comprehensive documentation on these properties on whats default. Again there are many annotations related to properties @ConfigurationProperties, @PropertySource, @Value, @EnableConfigurationProperties etc. Grails has this amazing single-point grailsApplication bean based on ConfigObject (a glorified Map) and allows nested and runtime evaluate-able configurations – helpful in dynamic scenarios. Again I wish Spring had defacto support for this (injecting properties from a config.groovy).

5. Rest Support (+)
SpringBoot makes it very easy to create rest controllers via @RestController. Instead of creating full-blown web applications, Spring’s eco can be used to create well-rounded rest services backed by Batch/Data/Integration/Security and use js frameworks like Angular/Knockout/Backbone etc. for front end. If using rest over json, Groovy 2.3 is promising to come up with fast json marshaller. While I like the cleanliness of Thymeleaf, the modern js frameworks have a clear advantage over server-side html generators.

6. Logging (+/-)
Yet again, too many logging frameworks in the bag: log4j, log4j2, slf4j, slf4j2, commons.log, java.util.log, logback. I spent some time resolving dependency conflicts, until I finally gave up and switched to logback. Spring team strongly recommends logback – Just Go with it – there is probably a good reason.

7. Data Access (+)
No question about Spring’s versatility here. Name any db and you have SpringBoot autoconfiguration support. Plus the Grails team has done a great job of spinning-off Gorm to standalone component. TexMex, I would say.

8. Testing (+/-)
Many examples still show use of JUnit, but here is a good start on how to use the incredible Spock framework in SpringBoot. Spock is like mom’s recipe – once you taste it, others aint the best.

9. Documentation (+)
It has improved a lot with newer minor releases. It takes time to sift through some old examples in the community, but lets just blame Google for not knowing what you exactly want, though it seems to know all about what food you want to eat when you are near a restaurant.

10. Finally
I think Grails3 (grails-boot?) is going down the trending route of embedded container deployments. I think that’s the only thing against Grails in the current trend. SpringBoot has got there first but I still feel it lacks the simplicity of Grails or the leanness of Play. It has certainly been simplified, but not simple.

If your existing eco system depends a lot on Spring based frameworks, it is worthwhile to adapt SpringBoot. Honestly, Im hoping Grails3 isn’t far off!