Sunday, December 31, 2017

Significant Software Development Developments of 2017

This post is my personal and opinionated assessment of some of the most significant developments related to software development in 2017. This is my eleventh year for this annual post and my previous years' assessment are available for 2016, 2015, 2014, 2013, 2012, 2011, 2010, 2009, 2008, and 2007. As with these previous years' assessments, this assessment of 2017's major developments in software development are obviously biased, opinionated, and limited to my perspective.

I think it important to re-emphasize that although this is an opinion-heavy post, the opinions are not on whether a particular language, framework, or tool is "best" or "worst." Rather, the opinions come in when deciding which of these frameworks, languages, or tools had the biggest developments of the year. I could, for example, decide that some language I hated had a big year and talk about its significant accomplishments of the year even if I loathe the language. Last year, at least one reader confused my listing of languages as endorsement of that being a better language, but this post is not that at all. Instead, this is a post of significant developments during 2017 in the software development world that I'm aware of. I obviously cannot be aware of every major software development happening in 2017 and welcome any feedback about major developments of 2017 in the world of software development.

One of the many challenges of writing a post such as this is that many of the subjects overlap significantly and it can be difficult to separate them and distinguish them. For example, the Internet of Things (IoT), Edge Computing, Cloud Computing, Big Data, Machine Learning, Artificial Intelligence (AI), and Software Security are all closely related and overlap to a degree.

10. Kotlin

2017 was a significant year for Kotlin. Kotlin 1.1 was released and moved JavaScript support out of "experimental." The release notes state that this JavaScript support "supports all Kotlin language features, a large part of the standard library, as well as JavaScript interoperability." The Kotlin 1.1 release also introduced (experimental) coroutines.

Kotlin 1.2 was also released in 2017 and built on the JavaScript support added by Kotlin 1.1 to add "the possibility to reuse code between the JVM and JavaScript."

The Technology Preview of Kotlin/Native was announced in 2017. The kotlin-native GitHub page describes Kotlin/Native as "an LLVM backend for the Kotlin compiler, runtime implementation, and native code generation facility using the LLVM toolchain" that is "primarily designed to allow compilation for platforms where virtual machines are not desirable or possible (such as iOS or embedded targets), or where a developer is willing to produce a reasonably-sized self-contained program without the need to ship an additional execution runtime."

Perhaps the biggest news for Kotlin in 2017 was its adoption as an officially supported program language for developing Android applications. The Kotlin Blog post "Kotlin on Android. Now official" opens with, "Today, at the Google I/O keynote, the Android team announced first-class support for Kotlin." The Kotlin on Android FAQ states that "Kotlin is fully supported in Android Studio 3.0 and higher." The 2017 4th Quarter Realm Report predicts that "2018 will be the year of Kotlin" and and that Kotlin will overtake Java as primary Android development language by December 2018.

Spring Framework 5 support for Kotlin was also announced in 2017. Wired features an article this year titled "Kotlin: the Upstart Coding Language Conquering Silicon Valley" and the Heroku Blog features a post "On the Rise of Kotlin". There are now multiple books available on Kotlin, most with publication dates in 2017. The Tiobe Index's December 2017 edition states, "The programming languages Kotlin and C seem to be the only candidates to become programming language of the year 2017" (Tiobe's programming language of the year is the "programming language that has the highest rise in ratings in a year"). Gabriela Motroc has published five proofs of "why Kotlin deserves to become the programming language of the year."

9. React

The main page for React.js describes it as "A JavaScript library for building user interfaces." This succinct description is perhaps a bit understated. React has received plenty of praise online this year and his been proclaimed by several blog post and article authors as the most popular choice for building front ends. The post "React.JS Top 10 Articles of The Year (v.2017)" highlights ten posts on React selected from nearly 12 thousand posts published in 2017. Similarly, the post "The most popular React links of 2017" highlights "the most popular links shared in 2017" from the year's editions of the React Status newsletter.

The popularity of React is proven by the influence the library has on general JavaScript development. For example, React's JSX that appears to mix JavaScript and HTML (it's really JavaScript with a HTML-like syntactic facade or "syntactic sugar") appears to be changing some opinions regarding the seeming mixing of JavaScript and HTML and there is now discussion about the differences between "separation of concerns" and "separation of technologies." In "JSX Looks Like An Abomination, But it's Good for You," Eric Elliott writes, "JSX is like a healthy vegetable that tastes like decadent chocolate cake. You feel guilty, but it's good for you."

8. Low-Code/No-Code

I've been a professional software developer long enough now to have seen many trends come and go, come again and go again. Throughout this time, there has been a seemingly constant effort to reduce the amount of code that needs to be written and maintained. We have come along way in many respects, but there is still a lot of custom code that is hand-written and much of it is redundant. Recently (and especially in 2017), the terms "low-code", "no-code", and "citizen developer" have become popular in this constant search for software development's holy grail.

Edward Hadley's "Low-Code Development Platforms Address Soaring Application Needs" explains the renewed recent interest in low-code and no-code solutions. He writes, "While the demand for custom applications has never been higher, traditional development approaches simply can’t keep pace. According to a statistic cited by Gartner, through 2021, market demand for app development will grow at least five times faster than IT capacity to deliver it." He adds, "The inherent value of a low-code development platform is that it brings IT and the business together." Jonathan Hult maintains a collection of "Low-code app builders" that "serve as a roundup post linking to low-code (or no-code) app (web/desktop) builders" and "should be citizen developer friendly."

It is postulated in The Atlantic article "The Coming Software Apocalypse" looks at the advantages of no-code/low-code/citizen developers from a different perspective. A central premise of this article is that many of the current and impending problems associated with software are due to general programmers not understanding well enough the problems they are trying to solve with code. Developers must focus on the instructions to the machine via code more than on the problem being solved. Nancy Leveson is quoted as saying, "The problem is that software engineers don't understand the problem they're trying to solve, and don't care to." She adds that the real problem is not being able to cover all the necessary requirements to be coded to in a manageable way. Bret Victor is quoted as saying, "I'm not sure that programming has to exist at all. Or at least software developers." He maintains that tools should be created to remove the need to work directly with code to solve the problems.

A paper by the Oak Ridge National Laboratory has a title starting with "Will humans even write code in 2040...?" starts its opening "Abstract" section with this statement, "Programming trends suggest that software development will undergo a radical change in the future: the combination of machine learning, artificial intelligence, natural language processing, and code generation technologies will improve in such a way that machines, instead of humans, will write most of their own code by 2040." One of the paper's authors (Jay Jay Billings) states in "Good code generators will be the most helpful and useful tools for coding by 2040" that he believes that "humans will still write code in 2040," but that "most code that we write now - what we might consider 'everyday code' - will be written with code generators that are fed by machine learning, AI, and natural language processing."

7. Blockchain

Primarily because of the mainstream interest in Bitcoin, many more people have become aware of the blockchain concept in 2017.

There are high expectations for blockchain. In "Blockchain: An Introduction," Arun Pandey writes that blockchain "helps transactions to have public witnesses and hence minimize cyber crime and fraud" and "serves as an open, distributed ledger to record transactions between two parties in a verifiable and lasting way." The article "What is Blockchain Technology? A Step-by-Step Guide For Beginners" states that "blockchain is an undeniably ingenious invention" that has "created the backbone of a new type of internet ... by allowing digital information to be distributed but not copied." Gabriela Motroc has asked "eight blockchain influencers" if "blockchain [can] transform the world?"

6. Machine Learning (ML) / Artificial Intelligence (AI) / Big Data

The authors of the Harvard Business Review July 2017 cover story "The Business of Artificial Intelligence" write, "The most important general-purpose technology of our era is artificial intelligence, particularly machine learning (ML) - that is, the machine's ability to keep improving its performance without humans having to explain exactly how to accomplish all the tasks it's given." They cover ways that AI has already helped business, but also look at unrealistic expectations for AI.

Some interesting uses of machine learning are covered in online resources such as Machine Learning for Humans, How artificial intelligence and machine learning will disrupt legal space, Machine learning will not replace people in all jobs: Study, Reimagine Business for Machine Learning, and Falling into Machine Learning.

In "2017: The Year AI Floated into the Cloud," Jackie Snow writes that in 2017 "tech firms opened a new front in the battle to win users over in the cloud: the large-scale introduction of cloud-based AI." Computer Weekly has published its "Top 10 Artificial Intelligence Stories of 2017" and Zach Emmanuel writes, "Artificial intelligence (AI) has continued to gain prominence in 2017 as one of the biggest upcoming technologies."

Big Data remains "big" in terms of popularity. Alex Woodie's post "10 Key Big Data Trends That Drove 2017" details "10 of the biggest takeaways for the big data year that was 2017." The post "Big Data: Main Developments in 2017 and Key Trends in 2018" "considers what happened in Big Data" in 2017. A DZone post details select IT Executives' responses related to their "biggest surprises about big data and analytics" in 2017. The post "Top 10 Big Data Blogs of 2017" looks at SyncSort's top ten blog posts of Big Data in 2017, including the post "Just How Big is Big Data, Anyway?" The article "The rise of big data in 2017: Here are the top emerging trends" begins with, "We saw the rise of big data in 2017 and the trend will continue to gain speed. Accessing and preserving big data is now a common practice at almost all organizations."

One of the "big" stories in the world of Big Data is the European Union's General Data Protection Regulation (GDPR). According to its web page, the GDPR "was designed to harmonize data privacy laws across Europe, to protect and empower all EU citizens data privacy and to reshape the way organizations across the region approach data privacy." That page states that its effective as of 25 May 2018 and "at which time those organizations in non-compliance will face heavy fines." The "key changes" of the GDPR can be found in "GDPR Key Changes." Bozhidar Bozhanov has posted "GDPR - A Practical Guide for Developers."

Since the original publication of this post, Jack Hinckley has posted "Big Data Made Big Strides in 2017". Hinckley writes in the opening paragraph, "2017 will be known as the year that Big Data went from buzzword on tech blogs and into practice at companies and organizations around the globe. ... We can now say, the time of Big Data on a large scale has arrived."

I might have "cheated" a bit to include artificial intelligence, machine learning, and Big Data all in one item, but they are closely related in many scenarios. Posts and articles talking about these together include "How Big Data Is Empowering AI and Machine Learning?", "Why AI, Machine Learning And Big Data Really Matter To B2B Companies," "Artificial intelligence, machine learning, deep learning and beyond," and "How Big Data Is Empowering AI and Machine Learning at Scale."

5. Containers

Containers continued to be a popular topic in 2017.

The Docker Blog has collected its Top Five Blogs of 2017 that include the posts Build and Run Your First Docker Windows Server Container and Exciting new things for Docker with Windows Server 1709. That blog also features a post Top 5 Docker Customer Success Stories in 2017.

2017 was an especially big year for Kubernetes. Christopher Tozzi writes in "Kubernetes’ Big Triumph of 2017: Killing Docker" that "the biggest change of 2017 in the world of containers" is "Kubernetes’s rise to dominance." He adds, "Kubernetes has taken the container ecosystem by storm. It has basically become the new Docker, in the sense that it is the name that now dominates most conversations about container technology." The Docker page "Adding Kubernetes support in the Docker platform" discusses Kubernetes integration with Docker in greater detail.

Chris Short has written a post Docker, Inc is Dead in which he opens with the sentence, "To say that Docker had a very rough 2017 is an understatement." He adds, "People will look back on 2017 as the year Docker, a great piece of software, was completely ruined by bad business practices leading to its end in 2018."

4. DevOps

The term "DevOps" seems to be written about and talked about more than ever. Everything I wrote about DevOps in last year's post remains true but to an even (much) larger degree than last year: "Although the DevOps concept has been around for a while now, it's gained popularity with the 'suits' (management) and the term is thrown around in all types of contexts. Software product vendors emphasize how their products continue to DevOps and software development requisitions and job listings are filled with references to experience with DevOps."

In my perusal of blog post titles and headlines each day, I see numerous references to DevOps. In just this week, posts on DevOps that have crossed my screen include DevOps remains a competitive advantage, Kubernetes news, DevOps developments dominate 2017 for IT shops, and Top 10 DevOps articles of 2017: The Enterprisers Project. Two (of many) examples of DevOps being embraced by the highest levels of management is the existence of the Forbes article "10 Top DevOps Barriers And Trends Forecasted For 2018," "2017 Brought More Open Standards for DevOps," and the DZone questions and answers format "Concerns With DevOps."

DZone has published "2017 DevOps Surprises" that contains observations from "IT executives" regarding the "biggest surprises about DevOps" in 2017. Forrester called 2017 the year of DevOps and predicts 2018 to be "The Year of Enterprise DevOps." Stanislav Ivaschenko has posted "Hopes and Fails in DevOps 2017."

3. Microservices

I cannot think of a software development related term that I heard or read more about during 2017 than "microservices." The term has been used for several years now, but 2017 seemed to see more use of it than ever. The Register recently featured an article called "Microservices 101" that introduces microservices for those who may not have heard much about them yet. Vendors are pushing microservices, which always means hearing a lot about them. "The State of Microservices Survey 2017 - Eight trends you need to know" provides observations from a survey of developers using microservices.

2. Cloud Computing / Internet of Things (IoT)

Cloud computing and the Internet of Things (IoT) continue to become more pervasive in our lives as consumers and therefore, not surprisingly, as software developers.

Recent articles on cloud computing in 2017 include "The Cloud in 2017: Amazon Web Services shows no signs of slowing during the year of Kubernetes," "2017 Cloud Computing and Data Center Industry Review and Conclusion," "8 resources for understanding the open source cloud in 2017" ("2017 was a big year for open source cloud computing tools"), "Cloud computing: Getting bigger but more complicated too," "Top cloud providers dominate headlines in 2017," "2017 cloud computing headlines show upside, hurdles for CIOs," "The top 10 Thoughts on Cloud articles of 2017," "Cloud Computing - What’s The Big Deal," "10 Benefits and Advantages of Cloud Computing," and forward-looking "5 cloud computing trends for 2018".

Sierra Wireless has published a post called "Internet of Things Year in Review: 2017." Other recent articles on the Internet of Things include "The internet of things: Why it matters," "Rise of the machines: who is the ‘internet of things’ good for?," and "2017 Internet Of Things (IoT) Intelligence Update,"

There have also been recent articles with ominous tones regarding internet of things such as "The Internet of Things' Dangerous Future," "The Internet of Things Needs a Code of Ethics," "Is This a Setback for the Internet of Things?," and "The dark side of the internet of things". Securing devices connected to each other via the internet of things is going to remain (or become in some cases) a high priority.

1. Software Security and Software Outages

I'd love to not have software security issues and software outages not top my list, but 2017 seemed to see even more negative incidences related to software security and software availability than ever. Michael Novinson writes that "data breach activity continued to skyrocket in the first 11 months of 2017, with the numbers of breaches jumping to 1,202, according to a report from the Identity Theft Resource Center and CyberScout," which is "up 10 percent from the 1,093 breaches recording during the entirety of 2016." John Zorabedian writes that 2017 "featured daily news about cyberattacks, data breaches, and software vulnerabilities." He adds, "If it feels like our cybersecurity challenges grow bigger and more complex, year after year, it's more than just a perception."

Here is a list of headlines from 2017 that highlight this increased frequency.

DZone has featured two posts on "2017 Security Surprises": Part 1 and Part 2.

Honorable Mention

The following did not make my top ten, but nevertheless saw major developments in 2017. Many of these items would likely make a different developer's top ten. There is no significance implied by the order of these listed entries in the "Honorable Mention" section.

"Serverless" / Function as a Service (FaaS)

I first started paying attention to the term "serverless" when the Fn Project was announced at JavaOne 2017 and especially after reading 8 Reasons why we built the Fn Project. The Martin Fowler article "Serverless Architectures" introduces these concepts well and the InfoQ article "FaaS, PaaS, and the Benefits of the Serverless Architecture" looks at the benefits of using these and talks about "nanoservices." Matt Watson's "What Is Function-as-a-Service? Serverless Architectures Are Here!" is also a good introduction to this topic and when FaaS and "serverless" might make the most sense to use.

Edge Computing

Often closely associated with Internet of Things (IoT), edge computing is described in GE Digital's What is Edge Computing? blog article as "computing infrastructure that exists close to the sources of data ... [on] devices [that] typically reside away from the centralize computing available in the cloud." The Wikipedia entry on edge computing adds, "Edge computing pushes applications, data and computing power (services) away from centralized points to the logical extremes of a network." The previously cited GE Digital article also differentiates Edge Computing versus Fog Computing and Edge Computing versus Cloud Computing.

Quantum Computing and Microsoft Q#

The concept of quantum computing is nothing new, but Microsoft's series of announcements of its Microsoft Quantum Development Kit Preview in the fourth quarter of 2017 seem to me to be a very significant development for quantum computing in 2017 because it feels like an early step toward taking quantum computing mainstream. The Microsoft Quantum Development Kit includes Microsoft's Q# programming language (including standard library and compiler) along with a "local quantum machine simulator" and a Q#-oriented extension for Visual Studio.

A post in early 2017 titled "Quantum computers ready to leap out of the lab in 2017" states, "Quantum computing has long seemed like one of those technologies that are 20 years away, and always will be. But 2017 could be the year that the field sheds its research-only image."

A nice introduction to quantum computing (at least as far as the little I understand about the subject allows me to detect) can be found in the aptly named "An Introduction To Quantum Computing." Microsoft has also provided an introduction in "What is quantum computing?" Forbes has published "15 Things Everyone Should Know About Quantum Computing."

An editorial in The Guardian calls the "the great power contest to develop a quantum computer" the "space race of our times." The following are some events and announcements related to quantum computing that occurred in 2017:


In "Mozilla Made the Web Better for Developers in 2017," Dustin Driver writes that "by the end of 2017, all the major browsers shipped support for WebAssembly, making the web a speedier and more robust place for everyone." The article "WebAssembly Will Finally Let You Run High-Performance Applications in Your Browser" discusses the history behind WebAssembly and "Introduction to WebAssembly: why should we care?" provides a nice introduction to WebAssembly, what it is, and why it will change web development and the user experience on the web.

Reactive System / Reactive Programming

The Reactive Manifesto was published in September 2014 and the reactive design concept seems to have grown in popularity each year since, especially becoming well-known in 2016 and 2017. The Red Hat Developers Blog features a post "5 Things to Know About Reactive Programming" in which Clement Escoffier defines "reactive programming" as "a development model structured around asynchronous data streams." Escoffier emphasizes that reactive programming is not the same thing as a reactive system: "Using reactive programming does not transform your system into a Reactive System. Reactive Systems are the next level."


TypeScript continued to see increased adoption in 2017. Mary Branscombe's post "Why TypeScript Is Growing More Popular" explains some of the reasons for this rise in popularity. Microsoft Technical Fellow and TypeScript developer Anders Hejlsberg is quoted in this article, "There's no doubt the partnership that we have with the Angular team has helped drive the numbers. ... Lots of other frameworks are using TypeScript at this point. Aurelia, Ionic, NativeScript are all, in one way or another, involved in TypeScript. The Ember framework, the Glimmer framework that was just released is written in TypeScript."

Two other posts in 2017 commenting on the rise of TypeScript popularity are "JavaScript for squares: The incredible rise of TypeScript" and "TypeScript - a trend that keeps on trending."

TypeScript turned five in 2017 and saw several new releases in 2017 as part of its new release cadence:


Vue.js ("The Progressive JavaScript Framework") seems to be a JavaScript framework whose popularity is rising quickly. Kevin Peters has written an extensive post called "Vue.js review of 2017" that leaves little need for me to write more regarding Vue.js in 2017. However, an additional potentially interesting read is "This Week in Numbers: React Leads the Pack, Though Vue.js Makes Big Strides in China."


Angular 5 (pentagonal-donut) was released in 2017 and "focuses on making Angular smaller, faster, and easier to use," but not everyone is pleased. Angular 5.1 has also been released in 2017 as has beta 5.2 versions.

JAX's "Year in review: Angular in 2017" provides a more detailed month-by-month review of Angular-related news in 2017.


JavaScript continued to be a highly adopted and used programming language with just one evidence of that being the numerous libraries and frameworks associated with JavaScript covered in this very blog post. I won't cover individual developments in the world of JavaScript here because there are so many online resources covering similar material. One such post is "JavaScript in 2017: Year in Review, Predictions for 2018" in which Boris Cherny writes, "2017 has been a wild year for JavaScript and frontend development." The article "The most popular JavaScript links of 2017" highlights top stories in 2017 from the JavaScript Weekly newsletters. "JavaScript: Top Articles in 2017" highlights "popular JavaScript Articles and Tutorials on Codeburst in 2017."

There are numerous "state of JavaScript in 2017" type posts (several of these are interpretations or summaries of the first linked post) such as "The State of JavaScript - 2017" (see also "A Look Back at the State of JavaScript in 2017" and "I just asked 23,000 developers what they think of JavaScript. Here's what I learned."), "JavaScript developers prefer React, want to ditch Angular & are attracted to Vue.js", "State of JavaScript: TypeScript rises, Angular falls," "Brief Analysis of the State of JavaScript 2017 Results," "Angular, React and VueJS - The Rise of Client-Side Frameworks in 2017," and "Developer Ecosystem Survey 2017 - JavaScript."


Node.js remains popular in 2017 as proven by posts such as "Node.js State of the Union 2017," "This is what Node.js is used for in 2017 - Survey Results," and "The Node.js Community was amazing in 2017!"

Node.js releases in 2017 range from Node.js 7.4.0 through Node.js 9.3.0.


Mark Little of Red Hat is quoted in "Java: 2017 Surprises and 2018 Predictions", "This has been a big year for Java, with several significant developments contributing to the ongoing evolution of the technology. The most notable event in 2017 was Oracle’s announcement to more fully open up Java EE by moving it to an open source foundation - and the subsequent announcement that it had selected the Eclipse Foundation to host the initiative as a top-level project called Eclipse Enterprise for Java (EE4J)."

JDK 9 was released in 2017 with its much anticipated and long-awaited introduction of built-in platform modularity. There was a surprising amount of drama surrounding the naming of future versions of Java SE as well, but it seems that "JDK 10" has won out. Oracle has also announced changes the releases of versions of Java and differentiated between the "Oracle JDK ("commercial long term support offering" intended for "commercial and support customers") and OpenJDK (which will include access to "previously commercial features such as Java Flight Recorder").

IBM open sourcing its JVM in 2017 and it is called OpenJ9. Another big deal to the Java community in 2017 was the publication of the Third Edition of Effective Java, the first edition of this book covering very significant Java versions 7, 8, and 9. Java Code Geeks has posted "Top 10 JavaCodeGeeks posts for 2017" that presents "a compilation with the most popular posts for this year" including "JDK 9 is Feature Complete" and "JDK 9 is the End of the Road for Some Features."

See JAX's Year in Review: Java in 2017 for a detailed analysis of events in the world of Java that occurred in 2017. Ben Evans's article "Looking Forward to Java in 2018" looks briefly at 2017 for Java and then looks at what the future may hold for Java. JAX also has posted "Top 10 Java stories of 2017: Angular, Eclipse, ML, and more."


Swift 4 was released in 2017. Two resources for details on Swift 4 features are What's New in Swift 4? and What's new in Swift 4.0.

Guy Daher, a self-described "Swift developer evangelist," looks at What Stats and Surveys are saying about Swift in 2017.


Python's popularity continues to increase and it's one of the most-used programming languages available. The State of the Octoverse 2017 states that "Python replaced Java as the second-most popular language on GitHub, with 40 percent more pull requests opened this year than last." Python remains the fourth-most searched for programming language on the Tiobe Index. Python also topped IEEE Spectrum's The 2017 Top Programming Languages (July 2017). As evidence of Python's growing familiarity, there is word that "Microsoft Considers Adding Python as an Official Scripting Language to Excel."

Versions of Python released in 2017 include Python 3.3.7 ("final release" of Python 3.3.x that "has reached end-of-life"), Python 3.4.7, Python 3.5.3, Python 3.6.3, and Python 3.6.4.


Scala 2.12.4 was released and includes "improved Java 9 friendliness."

The first release of Scala Native (0.1) was announced in 2017 and its GitHub page states, "Your favorite language gets closer to bare metal." The main Scala Native page describes Scala Native as "an optimizing ahead-of-time compiler and lightweight managed runtime designed specifically for Scala."

Ammonite, an open source project dedicated to scripting with Scala, moved toward its 1.0 release in 2017 and Ammonite 1.0.3 is available at time of this writing.


The Rust programming language continues to grow in popularity in 2017. The Rust Programming Language Blog features a post "Rust in 2017: what we achieved" that covers the highlights of achieving Rust goals in 2017 related to a "single overarching theme" of "increasing productivity, especially for newcomers to Rust." Jimmy Cuadra posted in 2017 "The highs and lows of Rust (2017)." The blog posts "Entering the Quantum Era - How Firefox got fast again and where it’s going to get faster" and "Mozilla Made the Web Better for Developers in 2017" discuss how Rust was an integral part of making the Firefox web browser faster.


The "Go" programming language continues to gain in popularity in the development community. In early 2017, Mariano Gappa wrote about Movio Cinema's Red Squad's adoption of Go. Around the same time, Keval Patel wrote "Why should you learn Go?" IEEE Spectrum lists Go in its "Top Ten Languages for the typical Spectrum reader" and InfoWorld's Paul Krill wrote "Go language soars to new heights in popularity."

The Go programming language in 2017 continued to head towards version 2.0 with releases that included go1.8, go1.9, go1.9.2, and go1.10beta versions.

The open source Joy project (Joy Compiler) for "translat[ing] idiomatic Go into concise Javascript that works in every browser" was introduced in 2017. The Joy FAQ states that it's possible that the Joy Compiler could one day allow for translating Go code to WebAssembly, but there are currently some hurdles to that happening.

In 2017, JetBrains announced the name for its Go IDE: GoLand. GoLand is a commercial (not open source) IDE that "extends the IntelliJ platform with the coding assistance and tool integrations specific for the Go language."

The Golang Weekly Team summarizes Go achievements in 2017 at the beginning of their Golang Weekly Issue 192.


C++17 (also known as C++1z) became "feature complete" in 2017. Bartlomiej Filipek has provided an overview of C++17 features in the appropriately named post "C++ 17 Features" and has posted "7 Features of C++17 that Will Simplify Your Code." The document "Changes between C++14 and C++17 DIS" covers "all the major changes that have been applied to the C++ working draft since the publication of C++14, up to the publication of the C++17..."

The JetBrains Developer Ecosystem Survey 2017 for C++ found that nearly two-thirds of the respondents currently use C++11 and a little more than one-third of the respondents currently use C++14 (respondents must have been allowed to indicate current use of more than one version of C++).


C has been named the Tiobe Index's "programming language of the year" for 2017. The "TIOBE Index for January 2018" states that C won this distinction primarily "because there were no outstanding alternatives" and explained at least part of C's resurgence on that index: "A possible reason for this revival is that C is very popular in the growing manufacturing and machine industry (including the automotive market)."


Josh Long, the Spring Developer Advocate at Pivotal, has written the post "This Year in Spring - 2017" in which he reviews "this very exciting year in Spring and its ecosystem." Some of the Spring-related highlights of 2017 covered in that post include the release of Spring Framework 5.0, release of Pivotal Cloud Foundry (PCF) 2.0, introduction of Spring Cloud Function, and Project riff ("a function service designed to run on Kubernetes").

Spring Framework 5 requires Java 8, includes support for Kotlin, and introduces a reactive programming model based on the Reactor project implementation of the Reactive Streams Specification for the JVM.


JUnit 5 was released in 2017 (General Availability in September and 5.1.0-M1 in November). JUnit 5 breaks JUnit tradition and is composed of three sub-projects (JUnit Platform, JUnit Jupiter, and JUnit Vintage). JUnit 5 requires Java 8 to run, but can be used to test Java code built against an older version of Java. Posts written in 2017 regarding JUnit 5 include Embrace JUnit 5, The Basics of JUnit 5 - A Preview (and A Look at JUnit 5's Core Features & New Testing Functionality), The five coolest new features of JUnit 5, What's New In JUnit 5?, and Seven Reasons Why You Should Start Using JUnit 5 Today.

I don't know enough about the software testing world to talk about general software testing developments of 2017, but Cynthia Dunlop's post "The Top Software Testing News of 2017" seems like a good place to start for such an overview. Dunlop opens the article, "It's not every year that 'software testing' hits the headlines across publications such as Forbes, Fortune, and Reuters. But these are no ordinary times for software testing. Agile and DevOps, which are designed to disrupt development, have also thrown software testing into turmoil—causing a shake-up in the software testing tools industry. This is evident by the string of software testing tool company acquisitions, spin-merges, and funding rounds that ended up dominating software testing news throughout 2017." One of the stories referenced and briefly described in that article is the InfoQ article "JUnit 5 is Released."

Munich Switches from Linux Back to Windows

In 2003, the city of Munich decided to move from Windows to Linux. This was an exciting time for Linux advocates in particular, but also for open source advocates in general. Unfortunately, there started to be some bad news coming out of this transition as early as 2004 and it was announced in 2017 that Munich would be returning to Windows. The reactions to this differ depending on who you ask (see "Munich Is Ditching Linux For Purely Political Reasons" and "Munich ends its long-running love affair with Linux"), but there's no doubt this move is a disappointment to the many open source and Linux users who thought the Munich "experiment" would lead the way for other world cities.

The switch from Linux back to Windows is likely far less devastating to Linux and open source adoption in 2017 than it would have been in te 2003-2004 timeframe. Open source and Linux are both well entrenched now and I don't see them losing ground in the near future. However, this is still a big enough story to make my "honorable mention" section and is the #2 story highlighted in the post "Biggest Linux News Stories of 2017."

Chaos Engineering

Introduced by NetFlix in 2014 (though used earlier by NetFlix) to help address issues seen more regularly with the rise of cloud computing and microservices, the principles of chaos engineering seemed to reach new heights of popularity in 2017. There were multiple articles and blog posts written on this topic in 2017 including InfoQ's Chaos Engineering, The Discipline of Chaos Engineering, How Chaos Engineering Can Bring Stability to Your Distributed Systems, Nora Jones on Establishing, Growing, and Maturing a Chaos Engineering Practice, Chaos Engineering at Netflix – What It Is & How It Works, and Designing Services for Resilience: Nora Jones Discusses Netflix Chaos Engineering at QCon SF. O'Reilly also made its free (when name and e-mail address are provided) ebook Chaos Engineering: Building Confidence in System Behavior through Experiments available.

Principles of Chaos Engineering describes chaos engineering as "the discipline of experimenting on a distributed system in order to build confidence in the system's capability to withstand turbulent conditions in production." O'Reilly's Chaos Engineering page states that chaos engineering is "a method of experimentation on infrastructure that brings systemic weaknesses to light" and adds that "this empirical process of verification leads to more resilient systems, and builds confidence in the operational behavior of those systems." Awesome Chaos Engineering is "a curated list of awesome Chaos Engineering resources."


Ruby 2.5 was released on Christmas Day in 2017 (a new release of Ruby on Christmas Day has become an annual tradition). Junichi Ito's post "10 new features in Ruby 2.5" introduces his "handpicked 10 new features" from Ruby 2.5's "new features and performance improvements."

There has been some discussion online about Ruby declining in popularity (Java and other languages have experienced such talk for years). In "Ruby on Rails is out: major coding bootcamp ditches it, due to waning interest," Matthew Hughes writes, "The pivot away from Rails shouldn't surprise anyone. While the framework continues to have a strong, cohesive community, and is actively developed and supported, developer interest has largely shifted elsewhere." Hughes also quotes Zed Shaw and Paul Watson on potential explanations for (slight so far) declining Rails popularity (newer competitors in web development with focus on front-end and single page applications).


PostgreSQL 10 was released in late 2017 and includes several new features such as logical replication, declarative table partitioning, improved query parallelism and other general performance improvements, and improved monitoring and control. PostgreSQL versioning is also changing with PostgreSQL 10 to a 2-digit version number instead of the old 3-digit version numbers.

PostgreSQL was named "DBMS of the Year 2017" by DB-Engines. The DB-Engines Ranking is updated monthly and "ranks database management systems according to their popularity." A particular database management system wins the annual prize for having the most significant increase in ranking over the 12 month period.


This post looked at some of the developments in software development that occurred in 2017. I undoubtedly missed some things and missed some developments associated even with some of the listed items. This post will be updated in the coming days and weeks as I remember some of these things or as feedback points out some of these missing items.

Tuesday, December 26, 2017

A Log Message is Executable Code and Comment

Although there are differences of opinion regarding how many comments one should add to one's code, I think it's safe to say most developers would agree that the comment in the following code snippet is superfluous:

// increment the total

In that example, the code is simple and really is self-explanatory with a decently named variable total being incremented with a standard Java operator. Fortunately, I don't see that obviously unnecessary type of comment as much now as I used to.

One area in which I still seem redundant comments more commonly than I'd like is associated with code situations that lead to explanatory log statements. Especially when the situation that leads to the log statement is a bit tricky, there occasionally seems to be a desire to write a comment to the developer who will be reading and maintaining that code in the future along with a desire to log relevant information for use in debugging the special condition later. In most of these cases, a well-crafted log message (like other well-crafted executable code) can speak for itself and doesn't require additional commentary.

Although writing logging code that is self-documenting is largely similar to writing any executable code that is self-documenting, logging code offers the advantage of being able to express arbitrary details within a log message. Normal code is limited by the constructs supported by the programming language and there may be times when the language's constructs are not as conducive to expressing intent as one would like. Logged messages are far less restrictive in terms of what can be articulated. On the downside, logged messages are often more likely to be neglected when changes to the code are made. Code changes must be made, but often log messages can remain unchanged (even if they should have been changed) and this omission may not be noticed until the statement is logged at some point in the future. Still, logged messages have a better chance of being changed/updated than do comments, which are only exposed during code reading.

An incidental benefit of using log messages to express special conditions instead of code comments is that this can lead to greater discipline in writing concise but thorough log messages. Another benefit of "commenting" via logged messages rather than in-code comments is that the messages can be written at runtime when the situation occurs and provide valuable insight into the code's behavior that was simply not available when analyzing the static code.

The following are two code listings, one using an in-code comment and the other using logging, to express the same sentiment to developers maintaining this code in the future. In both cases, the business logic consideration being documented is that the National Football League (NFL) Super Bowl in 2016 (won by the Denver Broncos) was not named with the traditional Roman Numeral naming convention. Instead of being named "L" as was anticipated based on earlier Super Bowls, this one was named "50". This is a contrived example of the type of business logic rule that is often expressed as a comment in code. Line 10 is the focus of each code listing here.

private int convertToSuperBowlYear(final String superBowlNumber)
   int superBowlYear;
   if (superBowlNumber == null || superBowlNumber.isEmpty())
      superBowlYear = 0;
   else if (superBowlNumber.equals("L"))
      // Super Bowl 50 was not named with the conventional Roman Numeral, so using '50' instead of 'L'
      superBowlYear = 2016;
      superBowlYear = getSuperBowlYearFromNumber(getDecimalNumber(superBowlNumber));
   return superBowlYear;
private int convertToSuperBowlYear(final String superBowlNumber)
   int superBowlYear;
   if (superBowlNumber == null || superBowlNumber.isEmpty())
      superBowlYear = 0;
   else if (superBowlNumber.equals("L"))
      logger.fine("Super Bowl 50 was not named with the conventional Roman Numeral, so using '50' instead of 'L'.");
      superBowlYear = 2016;
      superBowlYear = getSuperBowlYearFromNumber(getDecimalNumber(superBowlNumber));
   return superBowlYear;

Implementations for methods getSuperBowlYearFromNumber(int) and getDecimalNumber(String) are not shown here because they are not important to this discussion. The important thing here is that "L" is not a valid Super Bowl number and so "50" must be used instead of "L" when determining the year of the Super Bowl. A developer unfamiliar with the NFL or it Super Bowl naming convention and its departure from that convention for the 2016 Super Bowl need some type of comment to understand why one Super Bowl is treated differently than the others.

As a side note and speaking of Roman numerals, it is a bit surprising how many Java code examples are on the web for converting between Roman numerals and decimal-based integer. Some of these include Converting Roman Numerals To Decimal, Converting Roman Numerals to Decimal lying between 1 to 3999, Convert Roman numerals to decimal using Java, Convert roman numerals to decimal in java, and How To Convert A Roman Number To Integer. I suspect there are many homework problems inspiring this plethora of code samples.

Alexey has recently published the blog post "Replace TODO comments in your code with WARNING log messages maybe?" in which he states that he has started writing warning and error level log messages in situations in which he formerly wrote "TODO" comments. This is a more specific and more obvious example of using log messages instead of comments. In Alexey's case, he has been doing this because he realized that he "always forget about" the "TODO" comments and they "rarely get found and almost never get fixed." Alexey's conclusion is, "That's why I advise you to try this approach with writing your comments, your thoughts, and even your doubts into the logs: it will help you and can even entertain you and your colleagues!"

There are situations in which what one might add to in-source comments that would not be appropriate to add to log messages. Such situations include high verbosity of comments or sensitive nature of comments. It is also worth noting that some comment-level logged messages might never actually get logged because their log level would be set so specific that the log level would never actually be enabled during code execution. However, there are advantages in many scenarios to using concise but thorough log messages instead of in-code comments for communicating to future developers and your future self.

Saturday, December 23, 2017

Switch Expressions Coming to Java?

A JEP draft has been created with the title, "Switch Expressions for the Java Language." The current "Summary" states, "Extend the switch statement so that it can be used as either a statement or an expression, and improve how switch handles nulls. These will simplify everyday coding, as well as prepare the way for the use of pattern matching in switch." There are several promising characteristics of the proposed Java switch expression in its own right in addition to its enabling of the exciting Pattern Matching JEP (305).

The Java Tutorial defines a Java statement as a "complete unit of execution" that is "roughly equivalent to sentences in natural languages." It defines a Java expression as "a construct made up of variables, operators, and method invocations ... that evaluates to a single value." The current Java switch is a statement, but this draft JEP proposes that switch be supported as an expression as well.

The Switch Expression draft JEP states in its "Motivation" section, "As we prepare to enhance the Java Language to support pattern matching, several irregularities of the existing switch statement -- which have long been an irritation to users -- become impediments." The draft JEP is highly readable and contains interesting discussion points and illustrative code examples of how Java switch statement is currently often used within other Java constructors to effectively serve as an expression. The JEP draft shows how the proposal to extend switch to work as an expression in addition to being supported as a statement would improve the readability and maintainability of the code.

Java expressions need to "evaluate to a single value." The currently proposed switch expression would allow the break keyword to serve like a return in a Java method. A value could be specified following the break keyword and that value would be "returned" from the switch expression.

Because a Java expression "evaluates to a single value," a Java switch used as an expression would necessarily be required to provide a default value. An interesting twist on this covered in the draft JEP is for enums. The draft JEP states, "... in the case of an enum switch expression that covers all known cases (and eventually, switch expressions over sealed types), a default clause can be inserted by the compiler that indicates that the enum definition has changed between compile time and runtime. (This is what developers do by hand today, but having the compiler insert it is both less intrusive and likely to have a more descriptive error message than the ones written by hand.)" I found this particularly interesting because I've seen many cases where developers have either not written a "default" for a switch on the enum because all enum values at that time were covered by cases or have written a very generic error message. In fact, running into multiple examples of the latter are what finally led me to write my blog post "Log Unexpected Switch Options."

The draft JEP also covers some proposed enhancements that would benefit both the current switch statement and the new switch expression. One of these is the ability to indicate how to handle a null reference type passed to the switch statement. Today, for example, if one passes a null String to a switch statement, a NullPointerException is thrown. With this proposal, the developer could specify a case null clause. The current proposal would treat any null not explicitly handled as null is treated in switch today (by throwing a NullPointerException).

A second proposed beneficial feature for both current switch statement and proposed switch expression is to allow an individual case clause to support multiple potential matching values separated by commas. Three values for which the same behavior applies could be specified with a single case rather than with three case clauses sharing a single break.

The "switch expression draft" is still a draft that doesn't even have a number assigned to it yet and therefore is highly vulnerable to potential changes. Indeed, the proposal has already been discussed in the mailing lists and modified quite a bit, with an example being "Switch expressions -- some revisions." I found one message on the mailing list, "Switching on float/double/long," to be particularly interesting. This interesting message is full or technical and historical details including background on why today's switch statement does not support long and an interesting analysis provided by "resident floating-point expert" Joe Darcy regarding floating-point comparisons.

David Goldberg's 1991 article "What Every Computer Scientist Should Know About Floating-Point Arithmetic" is a well-known resource on understanding the complexities of floating-point arithmetic and representation. Darcy provides some interesting insight into some of these concerns and the IEEE 754 floating-point. He writes, "To address some common misunderstandings of floating-point, while it is often recommended to *not* compare floating-point values for equality, it is perfectly well-defined to do such comparisons, it just might not do what you want." Darcy addresses handling of NaN, positive zero and negative zero, and positive infinity and negative infinity. An interesting conclusion is that allowing switch on floating-point numeric type float could be implemented to really switch on the value provided by Float.floatToIntBits(float).

It appears that there could be some exciting times ahead for Java's switch if it is extended so that it can be used as an expression in addition to its current use as a statement. It's a development that could lead to cleaner code with less room for errors.

Friday, November 24, 2017

Too Many PreparedStatement Placeholders in Oracle JDBC

There are multiple causes of the ORA-01745 ("invalid host/bind variable name error") error when using an Oracle database. The Oracle 9i documentation on errors ORA-01500 through ORA-02098 provides more details regarding ORA-01745. It states that the "Cause" is "A colon in a bind variable or INTO specification was followed by an inappropriate name, perhaps a reserved word." It also states that the "Action" is "Change the variable name and retry the operation." In the same Oracle 12g documentation, however, there is no description of "cause" or "action" for ORA-01745, presumably because there are multiple causes and multiple corresponding actions associated with this message. In this post, I will focus on one of the perhaps less obvious causes and the corresponding action for that cause.

Some of the common causes for ORA-01745 that I will NOT be focusing on in this post include using an Oracle database reserved name (reserved word) as an identifier, extraneous or missing colon or comma, or attempting to bind structure names (rather than variables) to the placeholders.

In addition to the causes just listed and likely in addition to other potential causes of ORA-01745, another situation that can cause the ORA-01745 error is using too many ? placeholders in a JDBC PreparedStatement with the Oracle database. I will demonstrate in this post that the number of ? placeholders in a PreparedStatement that cause this ORA-01745 is 65536 (216).

I have blogged previously on the ORA-01795 error that occurs when one attempts to include more than 1000 values in an Oracle SQL IN condition. There are multiple ways to deal with this limitation and one of the alternative approaches might be to use multiple ORs to "OR" together more than 1000 values. This will typically be implemented with a PreparedStatement and with a ? placeholder placed in the SQL statement for each value being OR-ed. This PreparedStatement-based alternate approach employing ? placeholders will only work as long as the number of vales being OR-ed together is smaller than 65536.

The code listing that follows demonstrates how a SQL query against the Oracle HR schema can be generated to make it easy to reproduce the ORA-01745 error with too many ? placeholders (full code listing is available on GitHub).

Building Up Prepared Statement with Specified Number of ? Placeholders

 * Constructs a query using '?' for placeholders and using
 * as many of these as specified with the int parameter.
 * @param numberPlaceholders Number of placeholders ('?')
 *    to include in WHERE clause of constructed query.
 * @return SQL Query that has provided number of '?" placeholders.
private String buildQuery(final int numberPlaceholders)
   final StringBuilder builder = new StringBuilder();
   builder.append("SELECT region_id FROM countries WHERE ");
   for (int count=0; count < numberPlaceholders-1; count++)
      builder.append("region_id = ? OR ");
   builder.append("region_id = ?");
   return builder.toString();

The next code listing demonstrates building a PreparedStatement based on the query constructed in the last code listing and setting its placeholders with a number of consecutive integers that match the number of ? placeholders.

Configuring PreparedStatement's ? Placeholders

 * Execute the provided query and populate a PreparedStatement
 * wrapping this query with the number of integers provided
 * as the second method argument.
 * @param query Query to be executed.
 * @param numberValues Number of placeholders to be set in the
 *    instance of {@code PreparedStatement} used to execute the
 *    provided query.
private void executeQuery(final String query, final int numberValues)
   try (final Connection connection = getDatabaseConnection();
        final PreparedStatement statement = connection.prepareStatement(query))
      for (int count = 0; count < numberValues; count++)
         statement.setInt(count+1, count+1);
      final ResultSet rs = statement.executeQuery();
      while (
         out.println("Region ID: " + rs.getLong(1));
   catch (SQLException sqlException)
      out.println("ERROR: Unable to execute query - " + sqlException);

The next screen snapshot shows the ORA-01745 error occurring when the number of ? placeholders applied is 65536.

This example shows that there is a maximum number of ? placeholders that can be used in an Oracle SQL statement. Fortunately, there are other ways to accomplish this type of functionality that do not have this ORA-01475 limit of 65536 ? placeholders or the 1000 IN elements limit that causes an ORA-01795 error

Wednesday, November 22, 2017

Log Unexpected Switch Options

There are many things a Java developer can do to make his or her own life and the lives of others maintaining that code easier. In this post, I'm going to look at a very easy approach a developer can take to make things easier for everyone. The point of this post will likely seem obvious to everyone reading it, but I see this not done far more often than I would have expected. In short, developers should typically log the value they are switch-ing on when that value is not represented by any of the explicit case statements within that switch.

Before moving to specifics, I will add a few caveats. There are times when it may not make sense to log the value being switch-ed on that was not explicitly matched to a case. Some of these are listed here.

  • The value being switched on is sensitive and should not be logged for security reasons.
  • The value being switched on has numerous cases in which no match is expected and so the developer doesn't want to log unnecessarily.
  • A default can be provided that will always work well for any values that don't have matching case blocks (this seems rare).

In the cases I've seen that are the cause of this being one of my main pet peeves, none of the above caveats applied. In fact, in most of these cases, the developer has provided a logged message in the default block warning that the value was unexpected, but that same developer has failed to provide the candidate value that was not matched. A contrived example of this is shown in the next code listing.

Enum default That Logs Without switch Candidate Value

 * Provides the Roman numeral equivalent of the
 * provided integer.
 * @param integer Integer for which Roman numeral
 *    equivalent is desired.
 * @return Roman numeral equivalent of the provided
 *    integer or empty string ("") if I'm not aware of
 *    the Roman numeral equivalent.
public String getRomanNumeralEquivalent(final int integer)
   String romanNumeral;
   switch (integer)
      case 0:
         romanNumeral = "nulla";
      case 1:
         romanNumeral = "I";
      case 2:
         romanNumeral = "II";
      case 3:
         romanNumeral = "III";
      case 4:
         romanNumeral = "IV";
      case 5:
         romanNumeral = "V";
      case 6:
         romanNumeral = "VI";
      case 7:
         romanNumeral = "VII";
      case 8:
         romanNumeral = "VIII";
      case 9:
         romanNumeral = "IX";
      case 10:
         romanNumeral = "X";
         out.println("Unexpected integer was provided.");
         romanNumeral = "";
   return romanNumeral;

The issue here is really a specific example of a more general issue developers should avoid: logging without sufficient context. In some cases, it might be difficult or computationally expensive to provide the type of context that makes log messages more useful. That's typically not the case with switch statements, however, where we can easily log the value that we were trying to switch on. In the above code listing, developers supporting runtime issues in deployment will only be told that an "Unexpected integer was provided." Without any context, it's difficult to know what that provided integer was and, without knowing the candidate integer, it's difficult to trace what happened or even reproduce it.

Only very small effort is required to make this default logging statement useful and this is shown in the next code listing.

Constructing a Better default Log Statement

   out.println("Unexpected integer (" + integer
      + ") was provided, so empty String being returned for Roman Numeral.");
   romanNumeral = "";

The "enhanced" log message indicates which integer was being switched on and adds what is being returned because of that not being an expected integer. The second part is not as necessary for the developer because the static code will show the developer what is returned in that "default" case. However, the logging of the integer that was being switched on is highly valuable because there's no good way to access this information later unless a different log message somewhere else made it clear that's what was being switched on.

I have been the victim numerous times of developers not providing this simple context. It has made what would have likely been an easy diagnosis much more difficult. In extreme cases, I've had to add this context to the log message and wait for it to be encountered again. Had the developer added that simple context information at the time of writing of the code, the issue could have been resolved much more readily.

I like to take this concept a little further when writing my own switch statements. I typically add a default block even when my switch covers all possible (current) cases explicitly. This default block is unnecessary at the time of writing and will "never be called," but I add it to future-proof the switch statement (unit tests can be used to implement similar protections). I add the logging of the unexpected candidate value provided to the switch statement so that if another case is added "upstream" in the code, my switch will quickly tell me when it runs into an unexpected value and tell me what that unexpected value is.

It often turns out that having a candidate value for a switch statement without matching case is an exceptional circumstance. In such cases, it's likely more appropriate to thrown an exception than to simply log the exceptional situation. A standard exception such as IllegalArgumentException works well for this (it is, in a way, an illegal argument to the switch statement), but I have occasionally also written a custom exception to help with this. When I've decided to implement and use this custom exception, part of the reason for making that decision is that throwing of that exception encourages developers to provide the object being switched upon as part of the exception's constructor. A representative example of this type of custom exception is shown next (source code is also available on GitHub).

package dustin.utilities.exceptions;

 * Exception used to communicate a candidate value for
 * a {@code switch} statement not being matched by any
 * of the explicitly provided {@code case} blocks.
public class SwitchOptionNotExpectedException extends RuntimeException
    * Object being switched on for which no matching
    * {@code case} clause existed.
   private final Object switchedObject;

    * Constructor accepting exception message and the instance
    * upon which the {@code switch} was being attempted when no
    * matching {@code case} was found.
    * @param newMessage Exception summary message.
    * @param newSwitchedObject Object being switched on for
    *    which there was no explicitly specifed {@code case}.
   public SwitchOptionNotExpectedException(
      final String newMessage, final Object newSwitchedObject)
      super(newMessage + " (unable to switch on '" + String.valueOf(newSwitchedObject) + "')");
      switchedObject = newSwitchedObject;

    * Constructor accepting the instance upon which the {@code switch}
    * was being attempted when no matching {@code case} was found.
    * @param newSwitchedObject Object being switched on for
    *    which there was no explicitly specified {@code case}.
   public SwitchOptionNotExpectedException(final Object newSwitchedObject)
           "Switch statement did not expect '" + String.valueOf(newSwitchedObject)
         + "'.");
      switchedObject = newSwitchedObject;

    * Provides String representation of the object being
    * switched upon.
    * @return String representation of the object being
    *    switched upon.
   public String getSwitchedObjectString()
      return String.valueOf(switchedObject);

    * Provides type of object being switched upon.
    * @return Type of the object being switched upon or
    *    {@code null} if that switched upon object is null.
   public Class getSwitchedObjectType()
      return switchedObject != null ? switchedObject.getClass() : null;

Whether the developer is simply logging the switch candidate not being found or throws an exception is response to that, the value being switched on should typically be logged or included in the exception to make it easier to diagnose the issue. The custom exception above will provide that message automatically regardless of the constructor used as long as the developer provides the switched-on object. A developer would have to go out of his or her way to not provide that object in this case rather than simply neglecting or forgetting to include it.

After ruling out cases where it's not appropriate to log or write out the value being switched on that has no match, the mostly likely reason a developer fails to indicate the value is simply not thinking about it. It can be "obvious" to the developer at time of writing the code that any unexpected case "will never happen" or that it would be obvious what the value was if it did happen. Another likely reason for not including context in these types of messages (or any log messages for that matter) is being rushed or being lazy. A developer might know that it would be best to provide these details, but doesn't want to take the time to do it. It's this latter reason that sometimes encourages me to write a custom exception like that shown above.

Debugging and maintaining production software is a valuable experience for developers because it helps them to better understand how their actions (or lack thereof) make others' jobs more difficult in the future. In general, the conscientious developer can help others (and possibly himself or herself) by providing context information in logged messages, especially for warning, error, and exception conditions. In particular, adding the context of what value was being switch-ed on when no match is found is easy to do and could save yourself, other developers, and customers quite a bit of time in the future.