Generating JSON Schema from XSD with JAXB and Jackson

In this post, I demonstrate one approach for generating JSON Schema from an XML Schema (XSD). While providing an overview of an approach for creating JSON Schema from XML Schema, this post also demonstrates use of a JAXB implementation (xjc version 2.2.12-b150331.1824 bundled with JDK 9 [build 1.9.0-ea-b68]) and of a JSON/Java binding implementation (Jackson 2.5.4).

The steps of this approach for generating JSON Schema from an XSD can be summarized as:

1. Apply JAXB's xjc compiler to generate Java classes from XML Schema (XSD).
2. Apply Jackson to generate JSON schema from JAXB-generated Java classes.

Generating Java Classes from XSD with JAXB's xjc

For purposes of this discussion, I'll be using the simple Food.xsd used in my previous blog post A JAXB Nuance: String Versus Enum from Enumerated Restricted XSD String. For convenience, I have reproduced that simple schema here without the XML comments specific to that earlier blog post:

Food.xsd

<?xml version="1.0" encoding="utf-8"?>
<xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
           xmlns:dustin="http://marxsoftware.blogspot.com/foodxml"
           targetNamespace="http://marxsoftware.blogspot.com/foodxml"
           elementFormDefault="qualified"
           attributeFormDefault="unqualified">

   <xs:element name="Food">
      <xs:complexType>
         <xs:sequence>
            <xs:element name="Vegetable" type="dustin:Vegetable" />
            <xs:element ref="dustin:Fruit" />
            <xs:element name="Dessert" type="dustin:Dessert" />
         </xs:sequence>
      </xs:complexType>
   </xs:element>

   <xs:simpleType name="Vegetable">
      <xs:restriction base="xs:string">
         <xs:enumeration value="Carrot"/>
         <xs:enumeration value="Squash"/>
         <xs:enumeration value="Spinach"/>
         <xs:enumeration value="Celery"/>
      </xs:restriction>
   </xs:simpleType>

   <xs:element name="Fruit">
      <xs:simpleType>
         <xs:restriction base="xs:string">
            <xs:enumeration value="Watermelon"/>
            <xs:enumeration value="Apple"/>
            <xs:enumeration value="Orange"/>
            <xs:enumeration value="Grape"/>
         </xs:restriction>
      </xs:simpleType>
   </xs:element>

   <xs:simpleType name="Dessert">
      <xs:restriction base="xs:string">
         <xs:enumeration value="Pie"/>
         <xs:enumeration value="Cake"/>
         <xs:enumeration value="Ice Cream"/>
      </xs:restriction>
   </xs:simpleType>

</xs:schema>

It is easy to use the xjc command line tool provided by the JDK-provided JAXB implementation to generate Java classes corresponding to this XSD. The next screen snapshot shows this process using the command:

      xjc -d jaxb .\Food.xsd

This simple command generates Java classes corresponding to the provided Food.xsd and places those classes in the specified "jaxb" subdirectory.

Generating JSON from JAXB-Generated Classes with Jackson

With the JAXB-generated classes now available, Jackson can be applied to these classes to generate JSON from the Java classes. Jackson is described on its main portal page as "a multi-purpose Java library for processing" that is "inspired by the quality and variety of XML tooling available for the Java platform." The existence of Jackson and similar frameworks and libraries appears to be one of the reasons that Oracle has dropped the JEP 198 ("Light-Weight JSON API") from Java SE 9. [It's worth noting that Java EE 7 already has built-in JSON support with its implementation of JSR 353 ("Java API for JSON Processing"), which is not associated with JEP 198).]

One of the first steps of applying Jackson to generating JSON from our JAXB-generated Java classes is to acquire and configure an instance of Jackson's ObjectMapper class. One approach for accomplishing this is shown in the next code listing.

Acquiring and Configuring Jackson ObjectMapper for JAXB Serialization/Deserialization

/**
 * Create instance of ObjectMapper with JAXB introspector
 * and default type factory.
 *
 * @return Instance of ObjectMapper with JAXB introspector
 *    and default type factory.
 */
private ObjectMapper createJaxbObjectMapper()
{
   final ObjectMapper mapper = new ObjectMapper();
   final TypeFactory typeFactory = TypeFactory.defaultInstance();
   final AnnotationIntrospector introspector = new JaxbAnnotationIntrospector(typeFactory);
   // make deserializer use JAXB annotations (only)
   mapper.getDeserializationConfig().with(introspector);
   // make serializer use JAXB annotations (only)
   mapper.getSerializationConfig().with(introspector);
   return mapper;
}

The above code listing demonstrates acquiring the Jackson ObjectMapper instance and configuring it to use a default type factory and a JAXB-oriented annotation introspector.

With the Jackson ObjectMapper instantiated and appropriately configured, it's easy to use that ObjectMapper instance to generate JSON from the generated JAXB classes. One way to accomplish this using the deprecated Jackson class JsonSchema is demonstrated in the next code listing.

Generating JSON from Java Classes with Deprecated com.fasterxml.jackson.databind.jsonschema.JsonSchema Class

/**
 * Write JSON Schema to standard output based upon Java source
 * code in class whose fully qualified package and class name
 * have been provided.
 *
 * @param mapper Instance of ObjectMapper from which to
 *     invoke JSON schema generation.
 * @param fullyQualifiedClassName Name of Java class upon
 *    which JSON Schema will be extracted.
 */
private void writeToStandardOutputWithDeprecatedJsonSchema(
   final ObjectMapper mapper, final String fullyQualifiedClassName)
{
   try
   {
      final JsonSchema jsonSchema = mapper.generateJsonSchema(Class.forName(fullyQualifiedClassName));
      out.println(jsonSchema);
   }
   catch (ClassNotFoundException cnfEx)
   {
      err.println("Unable to find class " + fullyQualifiedClassName);
   }
   catch (JsonMappingException jsonEx)
   {
      err.println("Unable to map JSON: " + jsonEx);
   }
}

The code in the above listing instantiates acquires the class definition of the provided Java class (the highest level Food class generated by the JAXB xjc compiler in my example) and passes that reference to the JAXB-generated class to ObjectMapper's generateJsonSchema(Class<?>) method. The deprecated JsonSchema class's toString() implementation is very useful and makes it easy to write out the JSON generated from the JAXB-generated classes.

For purposes of this demonstration, I provide the demonstration driver as a main(String[]) function. That function and the entire class to this point (including methods shown above) is provided in the next code listing.

JsonGenerationFromJaxbClasses.java, Version 1

package dustin.examples.jackson;

import com.fasterxml.jackson.databind.AnnotationIntrospector;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.TypeFactory;
import com.fasterxml.jackson.module.jaxb.JaxbAnnotationIntrospector;

import com.fasterxml.jackson.databind.jsonschema.JsonSchema;

import static java.lang.System.out;
import static java.lang.System.err;

/**
 * Generates JavaScript Object Notation (JSON) from Java classes
 * with Java API for XML Binding (JAXB) annotations.
 */
public class JsonGenerationFromJaxbClasses
{
   /**
    * Create instance of ObjectMapper with JAXB introspector
    * and default type factory.
    *
    * @return Instance of ObjectMapper with JAXB introspector
    *    and default type factory.
    */
   private ObjectMapper createJaxbObjectMapper()
   {
      final ObjectMapper mapper = new ObjectMapper();
      final TypeFactory typeFactory = TypeFactory.defaultInstance();
      final AnnotationIntrospector introspector = new JaxbAnnotationIntrospector(typeFactory);
      // make deserializer use JAXB annotations (only)
      mapper.getDeserializationConfig().with(introspector);
      // make serializer use JAXB annotations (only)
      mapper.getSerializationConfig().with(introspector);
      return mapper;
   }

   /**
    * Write out JSON Schema based upon Java source code in
    * class whose fully qualified package and class name have
    * been provided.
    *
    * @param mapper Instance of ObjectMapper from which to
    *     invoke JSON schema generation.
    * @param fullyQualifiedClassName Name of Java class upon
    *    which JSON Schema will be extracted.
    */
   private void writeToStandardOutputWithDeprecatedJsonSchema(
      final ObjectMapper mapper, final String fullyQualifiedClassName)
   {
      try
      {
         final JsonSchema jsonSchema = mapper.generateJsonSchema(Class.forName(fullyQualifiedClassName));
         out.println(jsonSchema);
      }
      catch (ClassNotFoundException cnfEx)
      {
         err.println("Unable to find class " + fullyQualifiedClassName);
      }
      catch (JsonMappingException jsonEx)
      {
         err.println("Unable to map JSON: " + jsonEx);
      }
   }

   /**
    * Accepts the fully qualified (full package) name of a
    * Java class with JAXB annotations that will be used to
    * generate a JSON schema.
    *
    * @param arguments One argument expected: fully qualified
    *     package and class name of Java class with JAXB
    *     annotations.
    */
   public static void main(final String[] arguments)
   {
      if (arguments.length < 1)
      {
         err.println("Need to provide the fully qualified name of the highest-level Java class with JAXB annotations.");
         System.exit(-1);
      }
      final JsonGenerationFromJaxbClasses instance = new JsonGenerationFromJaxbClasses();
      final String fullyQualifiedClassName = arguments[0];
      final ObjectMapper objectMapper = instance.createJaxbObjectMapper();
      instance.writeToStandardOutputWithDeprecatedJsonSchema(objectMapper, fullyQualifiedClassName);
   }
}

To run this relatively generic code against the Java classes generated by JAXB's xjc based upon Food.xsd, I need to provide the fully qualified package name and class name of the highest-level generated class. In this case, that's com.blogspot.marxsoftware.foodxml.Food (package name is based on the XSD's namespace because I did not explicitly override that when running xjc). When I run the above code with that fully qualified class name and with the JAXB classes and Jackson libraries on the classpath, I see the following JSON written to standard output.

Generated JSON

{"type":"object","properties":{"vegetable":{"type":"string","enum":["CARROT","SQUASH","SPINACH","CELERY"]},"fruit":{"type":"string"},"dessert":{"type":"string","enum":["PIE","CAKE","ICE_CREAM"]}}}

Humans (which includes many developers) prefer prettier print than what was just shown for the generated JSON. We can tweak the implementation of the demonstration class's method writeToStandardOutputWithDeprecatedJsonSchema(ObjectMapper, String) as shown below to write out indented JSON that better reflects its hierarchical nature. This modified method is shown next.

Modified writeToStandardOutputWithDeprecatedJsonSchema(ObjectMapper, String) to Write Indented JSON

/**
 * Write out indented JSON Schema based upon Java source
 * code in class whose fully qualified package and class
 * name have been provided.
 *
 * @param mapper Instance of ObjectMapper from which to
 *     invoke JSON schema generation.
 * @param fullyQualifiedClassName Name of Java class upon
 *    which JSON Schema will be extracted.
 */
private void writeToStandardOutputWithDeprecatedJsonSchema(
   final ObjectMapper mapper, final String fullyQualifiedClassName)
{
   try
   {
      final JsonSchema jsonSchema = mapper.generateJsonSchema(Class.forName(fullyQualifiedClassName));
      out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonSchema));
   }
   catch (ClassNotFoundException cnfEx)
   {
      err.println("Unable to find class " + fullyQualifiedClassName);
   }
   catch (JsonMappingException jsonEx)
   {
      err.println("Unable to map JSON: " + jsonEx);
   }
   catch (JsonProcessingException jsonEx)
   {
      err.println("Unable to process JSON: " + jsonEx);
   }
}

When I run the demonstration class again with this modified method, the JSON output is more aesthetically pleasing:

Generated JSON with Indentation Communicating Hierarchy

{
  "type" : "object",
  "properties" : {
    "vegetable" : {
      "type" : "string",
      "enum" : [ "CARROT", "SQUASH", "SPINACH", "CELERY" ]
    },
    "fruit" : {
      "type" : "string"
    },
    "dessert" : {
      "type" : "string",
      "enum" : [ "PIE", "CAKE", "ICE_CREAM" ]
    }
  }
}

I have been using Jackson 2.5.4 in this post. The class com.fasterxml.jackson.databind.jsonschema.JsonSchema is deprecated in that version with the comment, "Since 2.2, we recommend use of external JSON Schema generator module." Given that, I now look at using the new preferred approach (Jackson JSON Schema Module approach).

The most significant change is to use the JsonSchema class in the com.fasterxml.jackson.module.jsonSchema package rather than using the JsonSchema class in the com.fasterxml.jackson.databind.jsonschema package. The approaches for obtaining instances of these different versions of JsonSchema classes are also different. The next code listing demonstrates using the newer, preferred approach for generating JSON from Java classes.

Using Jackson's Newer and Preferred com.fasterxml.jackson.module.jsonSchema.JsonSchema

/**
 * Write out JSON Schema based upon Java source code in
 * class whose fully qualified package and class name have
 * been provided. This method uses the newer module JsonSchema
 * class that replaces the deprecated databind JsonSchema.
 *
 * @param fullyQualifiedClassName Name of Java class upon
 *    which JSON Schema will be extracted.
 */
private void writeToStandardOutputWithModuleJsonSchema(
   final String fullyQualifiedClassName)
{
   final SchemaFactoryWrapper visitor = new SchemaFactoryWrapper();
   final ObjectMapper mapper = new ObjectMapper();
   try
   {
      mapper.acceptJsonFormatVisitor(mapper.constructType(Class.forName(fullyQualifiedClassName)), visitor);
      final com.fasterxml.jackson.module.jsonSchema.JsonSchema jsonSchema = visitor.finalSchema();
      out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonSchema));
   }
   catch (ClassNotFoundException cnfEx)
   {
      err.println("Unable to find class " + fullyQualifiedClassName);
   }
   catch (JsonMappingException jsonEx)
   {
      err.println("Unable to map JSON: " + jsonEx);
   }
   catch (JsonProcessingException jsonEx)
   {
      err.println("Unable to process JSON: " + jsonEx);
   }
}

The following table compares usage of the two Jackson JsonSchema classes side-by-side with the deprecated approach shown earlier on the left (adapted a bit for this comparison) and the recommended newer approach on the right. Both generate the same output for the same given Java class from which JSON is to be written.

/** * Write out JSON Schema based upon Java source code in * class whose fully qualified package and class name have * been provided. This method uses the deprecated JsonSchema * class in the "databind.jsonschema" package * {@see com.fasterxml.jackson.databind.jsonschema}. * * @param fullyQualifiedClassName Name of Java class upon * which JSON Schema will be extracted. */ private void writeToStandardOutputWithDeprecatedDatabindJsonSchema( final String fullyQualifiedClassName) { final ObjectMapper mapper = new ObjectMapper(); try { final com.fasterxml.jackson.databind.jsonschema.JsonSchema jsonSchema = mapper.generateJsonSchema(Class.forName(fullyQualifiedClassName)); out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonSchema)); } catch (ClassNotFoundException cnfEx) { err.println("Unable to find class " + fullyQualifiedClassName); } catch (JsonMappingException jsonEx) { err.println("Unable to map JSON: " + jsonEx); } catch (JsonProcessingException jsonEx) { err.println("Unable to process JSON: " + jsonEx); } }

/** * Write out JSON Schema based upon Java source code in * class whose fully qualified package and class name have * been provided. This method uses the newer module JsonSchema * class that replaces the deprecated databind JsonSchema. * * @param fullyQualifiedClassName Name of Java class upon * which JSON Schema will be extracted. */ private void writeToStandardOutputWithModuleJsonSchema( final String fullyQualifiedClassName) { final SchemaFactoryWrapper visitor = new SchemaFactoryWrapper(); final ObjectMapper mapper = new ObjectMapper(); try { mapper.acceptJsonFormatVisitor(mapper.constructType(Class.forName(fullyQualifiedClassName)), visitor); final com.fasterxml.jackson.module.jsonSchema.JsonSchema jsonSchema = visitor.finalSchema(); out.println(mapper.writerWithDefaultPrettyPrinter().writeValueAsString(jsonSchema)); } catch (ClassNotFoundException cnfEx) { err.println("Unable to find class " + fullyQualifiedClassName); } catch (JsonMappingException jsonEx) { err.println("Unable to map JSON: " + jsonEx); } catch (JsonProcessingException jsonEx) { err.println("Unable to process JSON: " + jsonEx); } }

This blog post has shown two approaches using different versions of classes with name JsonSchema provided by Jackson to write JSON based on Java classes generated from an XSD with JAXB's xjc. The overall process demonstrated in this post is one approach for generating JSON Schema from XML Schema.

Significant Software Development Developments of 2013

At the end of each calendar year, I like to summarize some of the most significant developments in the software development industry that happened during the year that is ending. The choice of these is entirely subjective and obviously colored by my own experience, background, perceptions, and preferences. Not worrying about the opinionated content of such a post, I now present the developments in software development that I consider most significant in 2013.

10. Gradle

Gradle appeared to me to enter the mainstream consciousness of software developers in a big way in 2013. I have been watching Gradle's development and playing with it a bit for some time now, but I have noticed that numerous open source projects now mention it prominently, it's referenced in many recently published Java books that aren't even about Gradle specifically, and Google selected Gradle to be delivered with its Android Studio product announced at Google I/O 2013. It took a while for Maven to breakthrough and compete with Ant and I think 2013 is seeing the beginning of Gradle's breakthrough to challenge Maven and Ant for predominance in Java-based build systems. Three books devoted to Gradle (the short Gradle: Beyond the Basics, the more comprehensive Gradle in Action, and the German Gradle: Modernes Build-Management - Grundlagen und Praxiseinsatz) have listed 2013 publication dates.

Gradle's rapidly rising popularity is nearly matched by its torrid rate of new releases. Gradle 1.4 ("faster builds that use less heap space"), Gradle 1.5 ("optimizations to dependency resolution"), Gradle 1.6 (improved Task ordering, "JaCoCo plugin for test coverage," and support for JUnit test categories), Gradle 1.7 ("fastest Gradle ever"), Gradle 1.8 (performance improvements and more native languages support), Gradle 1.9 (bug fixes and HTML dependency report), and Gradle 1.10 ("command-line usability features") were all released in 2013.

Gradle's success does not surprise me. It's Groovy foundation alone offers numerous advantages: Groovy scripts are easier to write procedural build-style code than is XML, Groovy has numerous syntactic shortcuts, Groovy is easily learned and applied by Java developers, Groovy has full JVM access, and Groovy includes built-in Ant support. On top of its inherent advantages from being built on Groovy, Gradle builds many useful and attractive features of its own on top of that Groovy foundation. Gradle adheres to several Ant and Maven conventions and supports Ivy and Maven repositories, making it straightforward to move from Maven or Ant+Ivy to Gradle.

Ruby on Rails helped bring Ruby into mainstream international prominence and, to a lesser degree, Grails helped do the same thing for Groovy. Gradle has the potential to pick up where Grails left off and push Groovy even further into the spotlight.

9. Trend Toward Single Language Development

For several years now, there has been a definite trend toward polyglot programming (polyglot persistence was even on last year's version of this post). Although this trend is likely to continue because some languages are better for scripting than others, some languages are better suited for web development than others, some languages are better suited for desktop development than others, some languages are better suited for realtime and embedded device development than others, some languages are better suited for scientific computing than others, and so on. However, I have seen indications of the pendulum swinging back at least a bit recently.

One of the arguments in favor of Node.js is the ability for JavaScript developers to use the same language on the "front-end" of a web application as on the "back-end." In the post Top Things I learned about development in 2013, Antonin Januska writes, "Working back to front in the same language is awesome." This is, of course, the reason that Java developers have in some cases been resistant to using JavaScript, Flex, or JavaFX Script (now deprecated) for front-ends of their Java applications (and why tools like Google Web Toolkit have been so popular). Java developers who write desktop applications (yes Virginia, desktop applications do exist) often experience the advantages of using the same language front-to-back as well.

One of Ceylon's most promising possibilities is the ability to write code in Ceylon that works on both Java Virtual Machines and JavaScript virtual machines and so could be used front-to-back in a Ceylon-based application. Indeed, the Ceylon page advertises, "[Ceylon] runs on both Java and JavaScript virtual machines, bridging the gap between client and server." Languages commonly associated with the Java Virtual Machine such as Scala and Kotlin also are offering the ability to compile to JavaScript.

A final example of the trend back to a single language in many environments is the use of Python in scientific computing as covered in the post The homogenization of scientific computing, or why Python is steadily eating other languages’ lunch.

I'm not arguing that this trend means that there will only be one main programming language in the future. However, I do believe it is generally human nature to want to use the same language or approach as much as possible because it's what we're familiar with and using the same language helps us to leverage our experience more broadly in the same application. The trend seems to be for each of the major languages (C/C++, Java, JavaScript, Python, .NET languages, etc.) to continue building up their own "stack" to support end-to-end functionality within that language and its ecosystem of frameworks, libraries, and tools. It's no coincidence that once a new language starts to see significant adoption, it quickly begins to see development of a variety of frameworks, libraries, and toolkits that extend the reach of that language.

I also don't want to imply that this is the end of polyglot programming. I don't see any programming language that is the best fit in all cases and there is no doubt that the most valuable developers will be those familiar with more than one programming language.

8. Internet of Things

I first heard about the concept of the Internet of Things at JavaOne 2012 and it got even more attention at JavaOne 2013. Oracle is not the only company touting the Internet of Things. IBM is into the Internet of Things as are many others.

Some believe that 2014 will be the year of the Internet of Things. Tori Wieldt has called "Java and the Internet of Things" one of the "Top Java Stories of 2013." In 2013, two series in Hinkmond Wong's Weblog have focused on the Internet of Things with featured posts on a Thanksgiving Turkey Tweeter and on a Christmas Santa Detector.

Other useful articles with differing opinions on the Internet of Things include The Internet of Things: a tangled web, Here's the Scariest Part of the Internet of Things, The Internet Of Things Will Be Huge—Just Not As Huge As The Hype, Five Challenges For The Internet of Things Ecosystem, The Internet of things will not arrive in 2014, CES 2013: The Break-Out Year For The Internet Of Things, and Here's Why 'The Internet Of Things' Will Be Huge, And Drive Tremendous Value For People And Businesses.

On a lighter (or more dire, depending on your perspective) note related to The Internet of Things, Aaron Pressman writes, "The whole crazy 'Internet of Things' movement to put everything under network control seems tailor made for Hal" (2001: A Space Odyssey).

7. Mobile Development

If someone not familiar with our industry was to start reading our software development social media sites and forums, that person would likely come to the conclusion that the vast majority of software development today is development of mobile applications. I have long argued that blog posts and articles often skew toward more leading-edge topics than established topics for a variety of reasons (perception/reality that established topics are already well-covered, resume building, fun to play with and write about new things, etc.). That being stated, there is no question that mobile development is popular in reality and not just in perception. There is no question that a big part of HTML5's popularity and rapid adoption is the opportunity to write applications in one set of languages (HTML/JavaScript/CSS) that will run on multiple mobile devices. Numerous projects and tools are being released to allow for writing applications in one language and compiling them to native formats for various mobile devices.

6. Responsive Design

At the end of 2012, Pete Cashmore predicted that 2013 would be the "Year of Responsive Web Design" because of its "obvious benefits": "You build a website once, and it works seamlessly across thousands of different screens." I like Jordan Larkin's explanation of responsive web design:

The term "responsive web design" (or responsive mobile design) refers to websites that change and adapt their appearance for optimum viewing on all screen sizes, tablets, smartphones, ipods, kindles along with desktop and laptop computer screens. Occasionally, in the digital arts industry, it is called "fluid design", "adaptive website design" or "RWD". Unresponsive websites do not change to fit different screen sizes, which means they can be difficult to navigate and look at on smaller devices.

As a person who is using a smartphone for an increasing percentage of my daily online activities, but still uses the laptop frequently and the desktop occasionally, I am appreciating firsthand the web site authors whose web sites and pages work well on all of these devices. It's often satisfactory to have two different web sites (one for mobile devices and one for everything else) from a consumer point of view, but this obviously means essentially duplicate code for the site developers. Even from a consumer point of view, there are times when I find the mobile version of a site lacking in features and in those cases it'd be preferable to have the regular site on all devices as long as that regular site appeared nicely on all devices.

The highly informative web site A List Apart has a nice set of articles related to responsive web design.

5. Node.js

JavaScript, despite its flaws, has dominated the web browser for years. Although JavaScript on the server has been available for some time (such as with Rhino and more recently Nashorn in Java), Node.js seems to be doing for JavaScript on the server what Ruby on Rails did for Ruby: the framework is popularizing the language (or in this case, popularizing the language specifically on the server).

2013 has been a big year for Node.js. There are numerous blogs and articles written on it on seemingly a daily basis. Some of these articles include What You Need To Know About Node.js and Node.js keeps stealing Rails' thunder.

Several books on Node.js have been published in 2013. These include Node.js in Action, Learning Node.js: A Hands-On Guide to Building Web Applications in JavaScript, Node.js the Right Way: Practical, Server-Side JavaScript That Scales, Pro Node.js for Developers, Node.js Recipes: A Problem-Solution Approach, Mastering Node.js, Using Node.js for UI Testing, JavaScript on the Server Using Node.js and Express, and the final version of The Node Beginner Book.

4. Big Data

Big Data holds the same #4 spot on my list as it did last year. Apache Hadoop and the R Project are just two examples of popular products/languages riding the Big Data wave. Python too, is increasingly being chosen as the programming language of choice for working with big data sets.

Readers of java.net recently answered a survey regarding Big Data in which the closest thing to a consensus seemed to be that "Big Data Is Probably Significant, but not too Surprising."

3. HTML5

HTML5 saw initial hype, disappointed for a while, and seems to be back on its rapid rise in popularity. I don't call out JavaScript individually in this post, but group it with HTML and CSS as part of HTML5 (and its also grouped with Node.js in this post). Given that HTML5, for purposes of this blog post, represents all of these things, it easily makes my top three significant software development developments in 2013. As mentioned previously with regard to mobile development, HTML5 is a popular approach for generating applications once that can theoretically run on any mobile device.

HTML5 features are seeing increasing standardization in terms of implementations in major browser. JavaScript/HTML libraries such as Angular.js and Ember.js are building on the momentum that jQuery has brought to HTML5 development in recent years.

HTML5's success is even evident in languages not considered part of HTML5 themselves. For example, one of the most heavily advertised new features of Java EE 7 is its HTML5 support. Recent versions of NetBeans IDE (considered primarily a Java IDE despite its multiple language support) have also seemed to emphasize HTML5 among their most important new features in 2013.

2. Security

As more information is online and we depend increasingly on availability of our data online, security continues to be an important issue for software developers. The trend of highly visibility security incidents continued in 2013. These incidents affected Ruby on Rails, Java, and other languages. The increasing frequency of security patches led Oracle to change how it labels the versions of Java SE.

An early 2013 article, Safeguard your code: 17 security tips for developers, outlines tips developers can take to improve the security of their applications. An earlier article in 2013 spelled out the increasing security concerns companies face. The book Java Coding Guidelines: 75 Recommendations for Reliable and Secure Programs has also been published in 2013. The 10 Biggest Security Stories Of 2013 outlines some of the biggest security-related stories of 2013.

1. Technical Dysfunction

Sadly, from a software development perspective, 2013 may be most remembered for the high profile technical glitches that occurred. Words like "debacle," "disaster," and "meltdown" have been associated with these issues and, rightly or wrongly, have reflected poorly on our industry. The most high profile dysfunction has been the embarrassing United States healthcare site healthcare.org. However, the issues that affect reputations and customer confidence have not been limited to government. Wal-Mart and Target, two major retailers in the United States, have had notable web site issues in the latter part of 2013 as well. Cloud-impacting technical dysfunction has occurred in 2013 in several notable cases including Amazon Web Services (AWS) and Google (including the search engine).

There seems to be plenty of blame to go around, but it seems difficult to get a good read on exactly what has caused these high profile technical failures. With healthcare.org, for example, I've seen people blame all types of different culprits including not allotting enough time to the effort, not being agile enough, being too agile, failing for despite agile approaches, failing to estimate user load correctly, getting government involved, etc. Although the real reasons are probably multiple and varied in nature and probably interest software developers more than others, the perception of our industry has gotten dinged up in 2013.

Honorable Mention

Although the developments in software development listed below did not make my top ten, they are significant enough to me to make this "Honorable Mention" category (in no particular or implied order).

JSON

One of the benefits of XML many years now has been the ubiquity of XML support across different languages, tools, frameworks, and libraries. For example, I recently wrote about how easy it is to use Groovy to search Subversion logs because Subversion makes its log output available in XML format and Groovy knows XML well.

JSON has been very popular with developers for some time now, but there have been many cases where standard libraries and tools that supported XML did not support JSON, meaning that developers had to write custom writing/reading code for JSON when using those libraries and tools. I'm beginning to see a lot more JSON support with tools and libraries now. Programming languages are also providing nice JSON parsing/writing capabilities. For example, Groovy has had JSON support for some time and Java EE 7 (JAX-RS 2.0) includes JSON support via the Java API for JSON.

JSON has been prominent enough in 2013 to warrant being included in titles of two Packt Publishing books published in 2013: JavaScript and JSON Essentials and Developing RESTful Services with JAX-RS 2.0, WebSockets, and JSON.

Java EE 7 Released

Java EE 7 was officially released in 2013. In a testament to Java EE's current widespread use and expected potential use of Java EE 7, book publishers have already published several books on Java EE 7 including Java EE 7 First Look, Java EE 7 Essentials, Beginning Java EE 7, Java EE 7 Recipes: A Problem-Solution Approach, Introducing Java EE 7: A Look at What's New, and Java EE 7 Developer Handbook.

Although I've never embraced JavaServer Faces (JSF), the feature of Java EE 7 that has been most interesting to me is the support for Faces Flows. I first read about this feature when reviewing Java EE 7 First Look and Neil Griffin's post Three Cheers for JSF 2.2 Faces Flows have reinforced my interest in this feature. In the post A Realistic JSF 2.2 Faces Flows Example, Reza Rahman supports my opinion that this is a key feature in Java EE 7 to watch with the quote, "Faces Flows are one of the best hidden gems in Java EE 7." Michael and Faces Flows might persuade me to give JavaServer Faces another look.

A recent blog post shows integration of AngularJS with Java EE 7.

Single Page Applications

The advantage of web applications over desktop applications has always been significant easier deployment of web applications than of desktop applications. The cost, however, has been a less fluid experience and sometimes less performing application than could be provided on the desktop. The concept of single-page applications is to make web (and by extension mobile applications that use traditional web technologies) feel and behave more like a "single-page" desktop application. Newer JavaScript libraries such as Meteor are being designed for the "thicker client" style of single-page applications.

The Wikipedia page on Single Page Application lists some technical approaches to implementing this concept. The Manning book Single Page Web Applications was also released in 2013. It's subtitle is "JavaScript end-to-end" (another piece of evidence of the general movement toward a single language).

See the description of Meteor below for another nice explanation of how web development is moving toward what is essentially this concept of single-page applications.

AngularJS

It seems like one cannot read any software development social media sites without running across mention of AngularJS. Although its Google roots are undoubtedly part of its success, AngularJS enjoys success from cleanly addressing significant needs in HTML/JavaScript development (shifting appropriate dynamic functionality from pure JavaScript to HTML with clever binding). In his post 10 Reasons Why You Should Use AngularJS, Dmitri Lau states that "Angular is the only framework that doesn’t make MVC seem like putting lipstick on a pig." Jesus Rodriguez, in his post Why Does Angular.js Rock?, writes that AngularJS "excels in the creation of single-page-applications or even for adding some 'magic' to our classic web applications." K. Scott Allen writes in his post Why Use AngularJS?, "I like Angular because I have fun writing code on top of the framework, and the framework doesn't get in the way."

Ember.js

Ember.js is another JavaScript library seeing significant online coverage in 2013. Ember 1.0 was released on 31 August 2013 and Ember 1.2.0 was released on 4 December 2013.

Like AngularJS and Knockout, Ember.js's approach is to embrace HTML and CSS rather than trying to abstract them away.

Famo.us

The famo.us web page currently requires one to "sign up for the beta" before being able to "experience famo.us." It's subtitle is "a JavaScript engine and framework that solve HTML5 performance." Another famo.us page states, "famo.us is a front end framework that solves performance for HTML5 apps" and "works for phones, tablets, computers and television."

Famo.us is discussed in two late 2013 InfoWorld posts: Did these guys just reinvent the Web? and Fast and flashy: Famo.us JavaScript framework revealed.

At this point, famo.us is still in beta, but it could be big in 2014 if it is able to deliver on what is advertised in 2013.

Meteor

Meteor is described on its main page as "an open source platform" for writing "an entire app in pure JavaScript" and using the "same APIs ... on the client and the server." In the Paul Krill interview Meteor aims to make JavaScript programming fun again, Matt DeBergalis stated that Meteor was created to address the changing web development paradigm often referred to as single-page application:

There is a shift in the Web application platform, and specifically, people are starting to write a new kind of application, what we call a thick client, where most of the code is actually running inside the Web browser itself rather than in a data center. This is an architectural change from running the software in the data center and sending HTML on the wire to a model where we have data on the wire and the actual rendering, the displaying of the user interface, is happening on the client. ... That's why it feels more interactive. It's not page-based like the old Web. It's much more engaging."

MEAN Stack

Having a witty acronym helped advertise and communicate the LAMP stack (Linux, Apache HTTP Server, MySQL/MariaDB, PHP/Perl/Python) and arguably contributed to the adoption of this combination of technologies. With this in mind, I found Valeri Karpov's post The MEAN Stack: MongoDB, ExpressJS, AngularJS and Node.js interesting. The post's author is another who points out the productivity advantages that can be gained from using a single language throughout an application. There is already a book underway: Getting MEAN with Mongo, Express, Angular, and Node. It will be interesting to watch this newly minted terminology and see if the stack and its name come close to the success that the LAMP stack and its name have enjoyed.

Commercial Support Dropped for GlassFish 4

Although it took longer to happen than most people probably anticipated, Oracle's dropping of commercial support for GlassFish 4 was formally announced in 2013 and is what most of us expected when we heard of Oracle purchasing Sun. The future of GlassFish is certainly cloudier now and expectations for GlassFish's future range from it being essentially dead to it thriving as the reference implementation.

Java IDEs

The major Java IDEs continued to add features to their already impressive feature sets in 2013. NetBeans had two major releases in 2013 with 7.3 released in February and 7.4 released in October. These two NetBeans releases added features such as Java EE 7 support, Project Easel for HTML5 development, Groovy 2.0 integration, JSON support, support for new JavaScript libraries (including Angular.js), native Java application packaging, Cordova integration, and improved support for non-JVM languages C/C++ and PHP.

IntelliJ IDEA 13 was released earlier this month. The release announcement highlights support for Java EE 7, improved Spring Framework integration, improved Android support thanks to IntelliJ IDEA Community Edition being used as the basis for Android Studio, improved database handling, and "refined Gradle support." Eclipse is often the IDE chosen for building a more specialized IDE such as Spring IDE (Spring Tool Suite), Scala IDE, or the new Ceylon IDE, so it's a particularly big deal that Google chose IntelliJ IDEA as the basis of its Android Studio.

Speaking of Eclipse, the seemingly most used Java-based IDE (especially when you consider the IDEs derived from it or based on it) also saw new releases in 2013. Eclipse 4.3 (Kepler) was released in 2013. There were also numerous popular plugins for Eclipse released in 2013.

Visual Studio 2013

Sun Microsystems was not the only company that saw desirable advantages and benefits from a single language that could be used at all layers of an application. Microsoft has implemented various efforts (Silverlight) for years to do the same thing. In 2013, Visual Studio 2013 was released with significant enhancements. These enhancements included improved support for languages not specific to Microsoft's .NET framework. Many of these better supported languages are on my list in this post: JavaScript, HTML, CSS, and Python.

Groovy

Groovy's 2.0 release (including static compilation support) made 2012 a big year for Groovy. Although 2013 did not see as significant of enhancements in the Groovy language, the year did start out with the announcement of Groovy 2.1. Perhaps the biggest part of that 2.1 release was Groovy's full incorporation of Java SE 7's invokedynamic, a major Java SE enhancement intended for non-Java languages like Groovy.

Groovy 2.2's release was announced toward the end of 2013. This release improved Groovy's invokedynamic support by adding OSGi manifests to the Groovy's invokedynamic-based JARs.

In The Groovy Conundrum, Andrew Binstock writes that "with the performance issues behind it, Groovy is a language primed for widespread use," but warns that Groovy is a language that is "easy to learn, but hard to master."

As is mentioned more than once in this post, Groovy has had a lot of additional exposure in 2013 thanks to Gradle's rapidly rising popularity. I believe that Gradle will continue to introduce Groovy to developers not familiar with Groovy or will motivate developers who have not looked at Groovy for some time to look at it again.

Scala

It seems to me that Scala continues to gain popularity among Java developers. I continue to see Scala enthusiasts gushing about Scala on various Java and JVM blog comments and forums. One piece of evidence of Scala's continuing and increasing popularity is the number of new books published in 2013 with Scala in their title. These include Scala in Action, Scala Cookbook: Recipes for Object-Oriented and Functional Programming, Functional Programming Patterns in Scala and Clojure: Write Lean Programs for the JVM, Scala Design Patterns: Patterns for Practical Reuse and Design, Play for Scala, Scala Object-Oriented Programming, and Getting Started with SBT for Scala.

For a much better background on what made 2013 a big year for Scala, see Jan Machacek's This Year in Scala (2013).

Ceylon

November 2013 saw "the first production release of the Ceylon language specification, compiler, and IDE." This announcement, available online at Ceylon 1.0.0 is now available, also states, "Ceylon 1.0 is a modern, modular, statically typed programming language for the Java and JavaScript virtual machines." Ceylon offers an Elipse-based IDE and has a formal specification. One of the factors favoring a successful future for Ceylon is its Red Hat sponsorship.

Kotlin

Kotlin is another language that compiles to the Java Virtual Machine or to a JavaScript virtual machine. It also has a strong sponsor in the world of Java in JetBrains, the company behind IntelliJ IDEA. 2013 saw several new releases of Kotlin: Kotlin M5.1, Kotlin M6, Kotlin M6.1, and Kotlin M6.2. I found the blog post Programming Android with Kotlin interesting because it demonstrates use of Kotlin and Gradle to build an Android application.

Go

The Go programming language has had strong backing from Google and continues to receive significant online coverage. Go 1.1 and Go 1.2 (with apparently improved performance) were both released in 2013. Of special interest to me is Go's advertised source code backwards compatibility for all versions 1.x.

Camel

2013 was a big year for Apache Camel, the tool that "empowers you to define routing and mediation rules in a variety of domain-specific languages." Camel-related developments in 2013 included the release of 2.11.0, release of 2.12.0, and release of 2.12.2. These frequent releases and the addition of a new committer and PMC member are among the signs of a healthy open source project.

The release of the Camel Essential Components (DZone Refcardz #170) kicked off 2013 for Camel. Camel got increased attention on software development social media sites in 2013. Zemian Deng's Getting started with Apache Camel using Java was syndicated on Java Code Geeks (as was his Apache Camel using Groovy Introduction) and Niraj Singh's Introduction to Apache Camel was also syndicated on Java Code Geeks. AndrejV's entire blog Just Did Some Code has so far (5 posts in 2013) been devoted to coverage of Camel!

Spring Boot

It's still early to tell because Spring Boot is currently only at version 0.5, but Spring Boot has potential to be be widely adopted and used in the future. It looks like Spring Boot is inspired by and takes advantage of some of the best ideas in Ruby on Rails and Groovy and applies them to easy generation of Spring Framework-based applications.

Python

As stated earlier, Big Data is big and Python is getting a share of that Big Data action. The Continuum Analytics post Python for Big Data states, "Python is a powerful, flexible, open-source language that is easy to learn, easy to use, and has powerful libraries for data manipulation and analysis. ... Python has a unique combination of being both a capable general-purpose programming language as well as being easy to use for analytical and quantitative computing." Tal Yarkoni echoes this statement and observes that his "scientific computing toolbox been steadily homogenizing" on Python.

Python 3.3.1, Python 3.3.2, and Python 3.3.3 were all released in 2013. Cython has joined Pyrex as an alternative for easily writing C extensions with Python syntax and there is even a book on Learning Cython Programming.

The article Python 3.4.0 goes to beta with slew of new modules talks about some of the new features coming with Python 3.4.0 (beta) such as a standard enumeration construct. The article also points out that one of the biggest frustrations with Python remains: the two versions of the language (2.x and 3.x) and no easy route from 2.x to 3.x. From a Java development perspective, I find this interesting because there was a time when arguments like Bruce Eckel's ("People who don't want to deal with these changes don't upgrade, and those people tend not to upgrade anyway") seemed logical and sensible. However, it's not quite as easy as it sounds, particularly when one starts to realize the impact of this on the entire set of products, libraries, and frameworks written for a language that can be heavily impacted and perhaps not usable for some time if ever with the new language.

PHP and HHVM

2013 saw the formal release of the PHP 5.5.x versions: PHP 5.5.0, PHP 5.5.1, PHP 5.5.2, PHP 5.5.3, PHP 5.5.4, PHP 5.5.5, PHP 5.5.6, and PHP 5.5.7.

At the beginning of 2013, Gabriel Manricks outlined reasons Why 2013 is the Year of PHP. Specifically Manricks described tools such as Laravel (including Eloquent ORM), Composer (dependency manager, including Packagist), and PHPUnit (test-driven development in PHP).

The Facebook project HHVM (HipHop Virtual Machine for PHP) was initially released in 2010, but seemed to see a lot more attention in 2013. The original HPHPc compiler compiled PHP into C++ and was another manifestation of the drive to use a single language for authoring an application even if its compiled form was different. The availability of the open source HipHop Virtual Machine (HHVM) for PHP should help address performance issues with PHP; that is seemingly Facebook's primary reason for developing it.

Android Studio

Android Studio was announced at Google I/O 2013 as "a new IDE that’s built with the needs of Android developers in mind" that is "based on the powerful, extensible IntelliJ IDEA Community Edition."

Cloud Computing

Interest in cloud computing remained strong and continued to grow rapidly in 2013. Many of the other items discussed in this post (Big Data, security, technical dysfunctions, etc.) have strong relationships to cloud computing. For more on the biggest cloud stories on 2013, see The 10 Biggest Cloud Stories Of 2013.

Internet Explorer 11

I have not used Internet Explorer except when forced to for a number of years. For a long time, I used Firefox almost exclusively and in recent years I've used Google Chrome almost exclusively on PCs and Firefox on Linux. When I have been forced by a particular web site to use Internet Explorer, I have done reluctantly and am reminded of the much slower performance of the browser than I'm used to in terms of startup and even navigation. I have noticed over this Christmas break, however, when I had to install Internet Explorer 11 manually because the automatic process kept failing, that it's a lot faster than even Internet Explorer 10 was. I still won't make it my primary browser, but it's nice that it performs much better when I do need to use it (such as to play Atari Arcade games without advertisements).

Internet Explorer 11 offers advantages for developers as well as users of the browser. Advertised benefits for developers (and by extension for users of these developers' applications) are improved standards compatibility, new F12 developer tools,

It's not all positive for Internet Explorer 11. Some people seem to want to downgrade to Explorer 10 and reportedly Internet Explorer 11 is presenting some problems for users of Microsoft's own CRM application (after earlier reportedly breaking Google and Outlook access).

It surprises me a bit that the main Microsoft IE URL (http://windows.microsoft.com/en-us/internet-explorer/download-ie) referenced by the Internet Explorer 11 Guide for Developers still advertises downloading of Internet Explorer 9, a version of that browser that Google has already stated they will no longer support.

Windows 8 Not As Successful

Windows 8 seems to be experiencing similar disappointment after Windows 7 that Windows Vista experienced after Windows XP. In fact, The 10 Biggest Software Stories Of 2013 states, "So it looks like Windows 7 will become the new Windows XP -- better get those downgrade rights ready."

Raspberry Pi

The Raspberry Pi continues to catch a lot of interest (2 million had been sold as of October of this year). There were seemingly endless posts on how to do a wide variety of things with the Raspberry Pi. Some of these that stood out most to me are Premium Mathematica software free on budget Raspberry Pi, GertDuino: An Arduino for Your Raspberry Pi, How an open-source computer kit for kids based on Raspberry Pi is taking over Kickstarter, Running OpenJFX on Raspberry Pi, and Simon Ritter: Do You Like Coffee with Your dessert? Java and the Raspberry Pi.

DevOps

The 10 Biggest Software Stories Of 2013 points out that "Cisco, Google and VMware last year invested in Puppet Labs" and that "another DevOps player, Opscode, raised $32 million and changed its name to Chef, the name of its flagship product."

Twitter Bootstrap

Bootstrap (alternatively known as Twitter Bootstrap and Twitter Blueprint) has become so popular and prevalent that there is now a popular (one of DZone's top posts in 2013)

post stating Please stop using Twitter Bootstrap. In August 2013, two years after the public release of Bootstrap, Bootstrap 3 was released (with 3.0.3 released in December). Everybody Should Code

The conversation of whether everybody should or code write code and develop software continued in 2013. Jessica Gross's writes about 10 places where anyone can learn to code and Megan O'Neil's article A Start-Up Aims to Teach Anyone to Write Computer Code features one of these places (Codecademy). Kevin Lindquist writes that software development isn’t just for coders anymore. Katie Elizabeth lists the reasons why everyone should learn to code while Chase Felker wonders if maybe not everybody should learn to code.

In 2013, President Obama (United States) asked America to learn computer science and it may be one of the few things Republicans and Democrats agree on, but Philip Bump argues, No, Mr. President, Not Everyone Needs to Learn How to Code.

SQL Strikes Back

NoSQL implementations have been all the rage for years, but 2013 seemed to present some resurgence in interest in SQL. Some NoSQL implementations added SQL or SQL-like syntax. SQLstream announces Return of the King: The Structured Query Language Is Back! and Jason Levitt and Sean Gallagher write "The hot new technology in Big Data is decades old: SQL."

The truth is that SQL never really went away and is heavily entrenched in software systems, but what is really interesting 2013 is the new thought and effort put into SQL development. word of Google's F1 SQL database ("a hybrid database that combines high availability, the scalability of NoSQL systems like Bigtable, and the consistency and usability of traditional SQL databases") is an example of this. Seth Proctor asks Do All Roads Lead Back to SQL? and writes of "NewSQL." In Software Development Trends for 2014, Werner Schuster states that "Many NoSQL DBs come with SQL or SQL-like languages" and asks, "Are SQL skills back in fashion?"

Conclusion

2013 may be remembered in popular culture as the year of selfies, but the developments in the software development world were far more substantive. In particular, it is interesting to see how developers in general are beginning to (or are remembering to) appreciate the ability to write an application front-to-back in a single language and to write responsive designs so that an application need be written only once for multiple platforms. The advantages of these approaches are not new to JVM (Java/Java EE) or CLR (.NET) developers, but seem to now be better appreciated by the more general developer community.

Previous Years' Significant Software Development Developments

The following are my posts similar to this one on items that I thought were of special import to software development in those respective years. I could definitely go back and add to some of these with things I've learned about since then for each of these years.

• 2012
• 2011
• 2010
• 2009
• 2008
• 2007

NetBeans 7.4 JSON Support

NetBeans 7.4 provides enhanced JSON support. The code folding and Navigator window support are demonstrated in a code listing for a simple Person.json file and how that code appears in the screen snapshots below.

Peson.json

{
   "person":
   {
      "firstName" : "Fred",
      "lastName" : "Flintstone",
      "city" : "Bedrock"
   }
}

The utility of being able to see the JSON in a tree-like manner in the Navigator and to code fold portions of the JSON is more obvious with more complex JSON. The next code listing and associated screen snapshots of that code in NetBeans 7.4 is based on JSON Example.

Glossary.json

{
    "glossary": {
        "title": "example glossary",
  "GlossDiv": {
            "title": "S",
   "GlossList": {
                "GlossEntry": {
                    "ID": "SGML",
     "SortAs": "SGML",
     "GlossTerm": "Standard Generalized Markup Language",
     "Acronym": "SGML",
     "Abbrev": "ISO 8879:1986",
     "GlossDef": {
                        "para": "A meta-markup language, used to create markup languages such as DocBook.",
      "GlossSeeAlso": ["GML", "XML"]
                    },
     "GlossSee": "markup"
                }
            }
        }
    }
}

Even though proper indenting can go along way toward making JSON more readable, the visual cues provided by the Navigator Window in NetBeans 7.4 make it even easier to see the relationships of nested data in a JSON file. The code folding also allows one to minimize desired levels of nested name/value pairs to be able to focus on whatever portion is needed at a given time. JSON is increasingly popular because of advantages inherent in this simple name/value format, but NetBeans 7.4 provides tooling that makes JSON even easier to use.

Book Review: JavaScript and JSON Essentials

Packt Publishing recently invited me to review JavaScript and JSON Essentials. They provided this book authored by Sai Srinivas Sriparasa in electronic format. Note that Sriparasa has also written a Packt Publishing article called Getting Started with JSON.

The Preface of JavaScript and JSON Essentials describes optional prerequisites for readers of the book: "It ... would be good to have some knowledge about HTML and JavaScript. Some familiarity with server-side languages such as PHP, C#, or Python would be preferred, but not required."

Chapter 1: JavaScript Basics

The initial chapter of JavaScript and JSON Essentials provides history and background on JavaScript. It describes JavaScript's relationship to HTML, CSS, and web browsers. It then moves to coverage of JavaScript syntax basics.

Chapter 2: Getting Started with JSON

The second chapter of JavaScript and JSON Essentials introduces JSON (JavaScript Object Notation) with a very brief historical background and emphasizes that "JSON is a format and not a language." The author wastes no time in touting some of the basics and virtues of JSON: "JSON is derived from JavaScript and bears a close resemblance to JavaScript objects, but it is not dependent on JavaScript. JSON is language-independent, and support for the JSON data format is available in all the popular languages." This chapter also provides a very basic comparison of JSON to XML as data interchange formats.

JSON's MIME representations, a sample Hello World example, and a comparison of JSON to JavaScript objects are all provided in the second chapter.

The second chapter includes other aspects you'd expect in a chapter introducing a format. For example, it describes JSON data types and programming languages that support JSON (with emphasis on PHP and Python).

Chapter 3: Working with Real-time JSON

With the basics of JavaScript covered in Chapter 1 and the basics of JSON covered in Chapter 2, Chapter 3 covers using JSON in "real-world applications." There is significant discussion and examples in this chapter of parsing and modifying static JSON with JavaScript.

Up until this point, the author used JavaScript's alert() to quickly and easily provide output from JavaScript code. I was pleased to see in this third chapter that the author explains the availability of console.log in modern browsers and explains some of the reasons console.log is preferred over alert().

Chapter 4: AJAX Calls with JSON Data

Chapter 4 moves JavaScript and JSON Essentials's focus from working with relatively static JSON data to working with dynamic JSON data. The chapter begins with a brief history of web application development and the move from synchronous communication to increasingly asynchronous communication (IFrame, XML HTTP ActiveX control, XMLHttpRequest). Sriparasa describes how the 'X' in AJAX (now commonly spelled Ajax) was originally for XML but that now JSON is commonly used instead of XML.

The fourth chapter spends considerable time explaining Ajax and demonstrating use of JSON with Ajax. The descriptive text and screen snapshots cover use of JSON with Ajax using straight JavaScript before demonstrating how to do this with jQuery (with emphasis on using jQuery.getJSON()). I really like that the author demonstrated implementing Ajax with direct JavaScript before introducing jQuery because I think it is advantageous to understand the underlying fundamental principles behind the libraries we use. This would probably be overkill in a book solely devoted to JSON, but seemed well-placed in a book that covers JavaScript's "essentials."

To illustrate the Ajax/JSON examples, Sriparasa first leads the reader through the "setting up Apache and PHP to develop server-side programs on a Linux machine" and "running a .NET-powered web application on Windows." As part of this, installation and use of the LAMP stack is covered and there are numerous screen snapshots of Visual Studio being used.

Chapter 5: Cross-domain Asynchronous Requests

JavaScript and JSON Essentials's fifth chapter begins with a deeper dive into the basic HTTP methods of GET and POST. The chapter mentions web debug tool Fiddler before going on to an example of POST-ing JSON data using jQuery.ajax() method, PHP, and MySQL. Another example in the fifth chapter leverages Reddit JSON-based APIs. JSONP (JSON with Padding) is introduced in Chapter 5 as part of the Reddit API-based example.

Chapter 6: Building the Carousel Application

The sixth chapter of JavaScript and JSON Essentials builds a "rotating notification board application" (a "photo gallery" style application) upon the concepts covered in the previous five chapters. The example is based on HTML, jQuery, and jQuery Cycle and spends a number of pages on applying jQuery Cycle.

Chapter 7: Alternate Implementations of JSON

The first six chapters of JavaScript and JSON focused on using JSON with HTML and JavaScript and on using JSON as a data interchange format, but the seventh chapter shifts focus to using JSON with other languages and in ways other than data interchange. Specifically, the author talks about using JSON capabilities of Composer (PHP) and Node Packaged Modules (Node.js) for dependency management, using JSON as a language-independent (Python and PHP get emphasized here) way to store application configuration data, and how JSON compares to YAML (described as "another software language-agnostic data interchange format").

Chapter 8: Debugging JSON

The final chapter of JavaScript and JSON Essentials, Chapter 8, looks at "different ways ... we can debug, validate, and format JSON." The chapter begins with a very high-level introduction to web browser support for diagnosing what's happening with JSON in the request or response and then delves more deeply into using Firebug with the Firefox browser and using the developer tools associated with Google Chrome, Safari, and Internet Explorer (F12) browsers.

Chapter 8's coverage of JSON validation tools looks at JSONLint. The author talso introduces JSON Editor Online as a JSON formatting tool. He explains some advantages of both tools and shows screen snapshots of each in use. Chapter 8's Summary's first paragraph summarizes the chapter and its other paragraph summarizes the book. One sentence from this book summary paragraph nicely summarizes what I feel is the ultimately accomplished objective of JavaScript and JSON Essentials: "JavaScript and JSON Essentials [is] targeted to provide you with an in-depth insight of how data can be stored and transferred in the JSON data format."

General Observations

• JavaScript and JSON Essentials seems best suited for developers with only very basic JavaScript background or who have not used JavaScript regularly since the mid-2000s because its focus is on use of JSON, Ajax, and other JavaScript related technologies that have been more prevalent since around 2005. There is an introductory chapter on JavaScript, but a person with no experience with JavaScript might want to prepare for this book by also reviewing online references such as Introduction to JavaScript for the total beginner and A re-introduction to JavaScript (JS Tutorial).
• JavaScript and JSON Essentials is a quick read. With eight chapters, just over 100 pages, and numerous screen snapshots (code and tools), this book is not overly long and does not waste a lot of space on unnecessary details.
• JavaScript and JSON Essentials uses numerous color screen snapshots to demonstrate code and applications. There are aesthetic advantages (such as color coded syntax and better visual separation of code from prose) with these images and they do provide a sense of realistic applicability, but one downside is that image snapshots of code cannot be copied and pasted. Fortunately, all code examples associated with this book are available for download.
• The screen snapshots of code listings have black and dark gray backgrounds with light fonts for the text. This works well for the electronic version of the book I reviewed, but it does not seem like it would work well nearly as well in a printed book with such dark backgrounds.
• There are some minor editing-related issues such as cases where one sentence that would fit on a single line in the book is spread over multiple lines with only a few words on each of the lines. There are only two or three of these cases and most of the prose is readable.

Conclusion

JavaScript and JSON Essentials introduces Java Script, JSON, and Ajax and some of the most important aspects of each along with how to use them together.