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 = {code here}

// 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?