Technological Musings

Thoughts of a technology enthusiast

Git Flight Rules

A great collection of situations and solutions for Git. Constantly evolving as it is hosted on Github and takes

If you see something missing, and know the solution, please add it.

Git Flight Rules

Java 9 is released. Summary of new features video

A great video summing up 55 New Features in JDK9. Well worth watching, as the presenter covers major and minor features, as well as deprecations.

Improvements to Collections including new, fast construction of List, Set and Map (finally). Discussions around Jigsaw, and a new linker that will allow creation of a module that ONLY contains the dependent jars/modules required.

Kotlin: The Java we've been waiting for

Awareness of Kotlin drastically increased after Google I/O, but if you’re not developing on Android, why should you care?

Well, let me tell you. Kotlin is the Java we’ve been waiting for.

Do you:
• Rely on your IDE to generate getters/setters/equals/hashCode?
• Use Lombok for defining data classes?
• Write lots of null check code, and lots of tests to verify null handling?
• Use annotations to verify null handling?
• Add external static analyzers for null verification?
• Leverage Optional (but only for return values, right?)
• Use Guava to provide a number of utilities?
• Use Apache commons libraries for many utility classes?
• Create utility classes that are effectively extensions for a Class?
• Create many overloaded functions in lieu of default parameters?
• Want to create DSL’s?

Then perhaps it’s time to switch to Kotlin. Yes, there’s some overhead in learning the language, and the compiler is a bit slower than Java’s, but given the items in the list above that need to be learned or known, and the extra processors for code generation and analysis, I think it’s a worthwhile transition, and ultimately isn’t any slower.

Data classes are built into the language. Getters, Setters, equals, hashCode and clone are all defined for it. Now when you’re reviewing code, you know immediately what’s defined for this class. No need to confirm that nothing is done in the setter/getter. No need to verify the implementation of equals/hashCode, or ensuring it has both.

If you use Lombok, you don’t have the above worries either, BUT you do require a plugin for your IDE, and additional build configuration to ensure the Lombok generator is executed.

Example data class that contains an immutable birthDate and mutable name property.

data class MyPojo(val birthDate: String, var name: String)

Null verification is built into the language. Just define the type, and it is non-null. To let the compiler know a variable is nullable, append a ? to the type. Very simple and readable.

The same applies to return values. No need to use a wrapper class (Optional) with all the new learning to use it property. (isPresent is not proper usage)

The compiler will verify via flow analysis, and unless you turn it off, verification will be performed at runtime.

No need to add annotations for non-null, or rely on conventions that all parameters are non-null. No need to wire in additional analysis/generation tools. No need to write code to verify parameters are non-null.

The standard library contains many extensions to common classes. Everything I’ve ever needed from commons-lang3 is in the Kotlin standard library. Guava Predicates is commonly used. Once again, this type of functionality is built into the Kotlin standard library.

And for comparison, Guava 22.0 is 2.6MB, while commons-lang3 3.6 is 495KB for a total of 3MB
while Kotlin stdlib is 881KB, stdlib-jdk8 is 12KB and stdlib-jdk7 is 3KB for a total of 896KB. Quite compact considering what it provides.

Kotlin provides extension functions so that you can provide additional methods on a Type whether it’s in your code base, or in a library. When writing code, extension functions look as if they’re defined on the Type (hence the name).

// Note, this already exists in stdlib
fun String.toUpperCase(): String = this.toUpperCase()
// and to use
val newString = "old string".toUpperCase()

Hopefully you see that Kotlin encapsulates a number of best practices and standards directly into the language and compiler, rather than on external libraries and tools regularly applied doing Java coding.

And this is only the beginning of the features that Kotlin provides that make code easier to review, and reduce the chance of common errors creeping into the code.

I will create follow up posts to cover more features/benefits of Kotlin. Next will be static analysis.

Diversity in Technology

Must watch video by Jez Humble - Continuous Delivery in Agile. The Last 20 minutes on Diversity are very impactful.

This was presented at Agile2017, and was primarily about Continuous Delivery. Jez does an excellent job explaining why this can be done anywhere, and debunks 4 common reasons given for not being able to do it ‘here’.

The last 20 minutes are very powerful. It needs to be it’s own talk on Diversity in technology as it is so compelling.

The talk was driven in response to James Damore’s letter to Google. Jez did a lot of research, and tears apart the letter, while providing his own explanations for why the lack of diversity exists.

The main determination is this. People believing that a skill is innate, and propagating that belief leads to alienation. Alienation drives people elsewhere.

This exposes itself as “This is too hard for you”. “You weren’t born with this ability” and similar thoughts.

He then shows a chart of female percentages in the Medical, legal, physical sciences and Computer Science fields. All 4 have been steadily increasing since the beginning of the chart. Then the 80’s arrive and it’s all down hill for CS. The others continue upwards and are close to 50%. Why? Please watch the video to see Jez’s explanation.

Everyone knows about the shortage of software developers. Here’s a large portion of the potential workforce, but they have no interest. This MUST change and it starts with each and everyone of us!

Use your commit history to tell a story

I always try and keep my commits focused on one thing. This was brought to my attention recently as I was doing a code review. A number of refactors mixed in with code changes.

Makes reviewing much harder to perform, and harder for both developer and reviewer to ensure things are correct.

Git has many features for helping with this. Find a refactor part way through a change, then pull out the refactor portion so it can go into its own commit, and continue with your code changes.

Doing a large refactor and want to make it smaller? Again, git supports that.

When coding, think about both your validation of the changes as well as a code reviewers view. As soon as there are more than 100 lines of code in a commit, and especially if there are a number of contexts, the review quality goes way down.

Why aren't you contributing to Open Source?

An interesting take on why your employer should support you contributing to Open Source, and why contributing to Open Source doesn’t have to mean using personal time.

If you’re a programmer today, you’re almost certainly taking advantage of Open Source libraries. These libraries are saving you (and by extension, your employer/clients) much money, time and effort.

Therefore your employer/client should be ok with you contributing to the libraries during working hours. Obviously it will be easier if you focus on libraries that are in use for the project, and preferably addressing issues you’ve encountered, or adding features that are valuable to you.

The other benefit is exposure to other’s code, peer reviews, and all around improvement of your own design and coding abilities.

Something to think about, and talk with your employer/client’s about if they don’t currently allow it.

Why don’t you contribute to open source?

Groovy as your primary language

Groovy is fantastic. Remind we why I still program in Java?

I’ve been watching some Groovy videos from the recent SpringOne2GX conference. I’ve always really liked Groovy, and use it for all my personal projects. It’s so much more succinct, and the tools around it are very powerful.

After watching these videos, and seeing even more power available, as well as the fantastic enhancements around Type Checking and static compiling, I’m left asking myself why I code in Java at all.

Almost all valid Java code is valid Groovy code, so it’s easy to transition at your own pace. Groovy then allows you to remove so much ceremony, plus has so many powerful additions. AST transforms for creating an Immutable object. Defining a POJO while only having to define the properties. Powerful DSL’s that if written correctly, are Type checked at compile time, rather than at runtime.

Spock testing framework combines all the power of Junit, Mockito and JUnitParams in an even easier to read and use DSL for testing.

Even if you use Spring Boot, there is very good support for using Groovy everywhere. The main language, as the templating language (the new Groovy MarkupTemplate DSL is fantastic. Type checked at compile time rather than runtime, and optimizations performed by the compiler to improve performance at runtime).

Replacing Spring Data with GORM (from Grails). Spring Data allows for reflection based methods, BUT these aren’t checked until run time, and are limited in their functionality.

Using the latest GORM DSL, the queries are checked at compile time, and are much more flexible and readable. Instead of relying on a very long method name, a closure is used to define the request.

Closure Example
people.find {
name == ‘George'

This will ensure the People object has a name property and an adult property at compile time.

DSL’s written correctly, are type checked at compile time, and your IDE can provide code assistance. Very powerful tool.

Watch the videos below and learn more about Groovy. I intend to incorporate it into my next project, and don’t want to code Java again.

Groovy after all these years at Mutual Life
Advanced Groovy Features
Modern approach to writing DSL

Site security: Use pass phrases and not complex passwords

An excellent article on how to enforce pass phrases and why they outperform traditional ‘secure’ passwords with complex rules.

It’s also much easier, and less frustrating for your users.

Why passphrases are more user friendly than passwords

I recently had to change my Atlassian password. The password input placeholder read ‘A few words you’ll find easy to remember’. Nice to see they’re following this advice.

Learning Stenography for super fast document production

After listening to this podcast, I want to learn more about Stenography.

Why do it?

Achieving 150-200wpm would be awesome. Sounds like a steepish learning curve, but a much larger payoff than learning Dvorak or Colemak.

IntelliJ IDEA memory settings

From Note: Site no longer active.

Give more memory to IDEA and it will perform better. No big surprise, but some recommendations based on 3 different approaches. I now use the ‘Balanced’, summarized below. More memory without starving everything else on the machine.

2GB for Xmx and 2GB for Xms, more balanced approach to the memory consumption


For Mac, it’s in ~/Library/Preferences/IntelliJIdea15/idea.vmoptions.
For Windows, it’s in Program Files (x86)/JetBrains/bin/idea.exe.vmoptions.

Update: IntelliJ provides a shortcut from the Help menu to customize the VM Options. It will open or create the file in the OS specific location. On the Help menu, choose ‘Edit Custom VM Settings’.