Posts Tagged: jvm

Using Optional in Java to check for null

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I see the need for null in Java still, but since the Optional class was introduced I think some of the usages of null can be eliminated by employing some of the capabilities of the Optional class. I will explain in this post a nice way you can implement checking for null in Java by […]

Common mistake when dealing with Reader in Java

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I’ve encountered this one a few times and came across again recently and thought it relevant to deserve its own post, so here it is. If you have done any I/O in Java you likely came across the Reader class, unlike the InputStream class(es) which deal with bytes, the Reader makes the transition into reading […]

Nicer implementations using Java streams

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I am not entirely sold on the performance of the Java streams but I will accept they are getting much better compared to the first cut, we now have parallel streams and all sorts, and also it provides a (nicer) functional approach to coding. I’m not going to go into the whole dispute of whether […]

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Java Dependency Injection and a Useless Annotation

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I’ve stepped into the Guice territory rather recently — coming from the Spring framework side of things — and I guess I had so far a similar love/hate experience as with Spring. I rely mostly on the javax.annotation standards anyway so to a certain degree whether it’s Spring or Guice I guess doesn’t make that much […]

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Java, Map and Optional

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I do like the Optional class in Java — it is a long awaited elegant replacement for returning null whenever something isn’t there then relying on if( x != null ) checks or using ?: in the format (x == null) ? “foo” : “bar”. It works great also with the new Java stream classes […]

Gotcha When Building Gradle Plugins on Top of docker-java-plugin

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If you use gradle and docker you must have come across the gradle-docker-plugin. And if you started using it a lot you probably found out that more often than not your builds start using the same boilerplate code to prepare your microservices containers. And if you end up in that situation best thing to avoid boilerplate rubbish […]

Of Fibonacci’s Number and Groovy’s Memoization

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As a developer, chances are every time you hear recursion mentioned you probably also hear of Fibonacci’s number. And in the same breath you probably hear also of stack overflow 🙂 Because — as you get to learn quickly — if you decide to implement Fibonacci’s number via a recursive function, you end up abusing […]

Gradle Multi-module Projects — Centralized Configuration

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This is a sweet gradle trick for those of you working on multi-module projects, if you are looking to centralize some of the configuration in the parent gradle build, and avoid repeating configuration / build code across sub-modules. Let’s say you have the following gradle project structure (see image below) where project A is the […]

Collection Sorting — Java vs Groovy

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With the introduction of lambdas in Java (not so) recently, some argue that Groovy lost some of its thunder, as closures are now first class citizens in the JDK. However, as I’m about to show, while lambda’s pushed the Java language a great deal forward, Groovy still makes a lot of things incredibly easy (and […]

A Bit of Lovin’ for the Groovy Object Initialization

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I’m going to spread some lovin’ today for the widely-used yet less appreciated feature in Groovy which allows creating a Java bean and setting its properties in one line. Especially when dealing with unit tests this saves me a great deal of time and frustration. If you ever worked with “pure” (??) Java beans, then […]

Parallel : Groovy and Java Streams

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This is something that every now and then I have to do: check whether either one or all elements of a collection meet a certain criteria. The standard code initially in Java involved a for loop and iterating through the collection explicitly and checking the condition at each step. Then Apache Commons came on with their […]

Goodies in Groovy from DefaultGroovyMethods

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If you ever programmed in Groovy language, you probably “enjoyed” (maybe without realising) the joys of DefaultGroovyMethods. What you probably don’t realise is that you can override these methods to customize your classes — and occasionally generate some code that’s not that easy to read. (Do you remember the old C++ way of overriding operators […]

On Java Annotations and Type Safety

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Nicolas Fränkel published a blog entry recently talking about “Type-safe annotations” in Java — which trigger my thoughts on the same matter, and voila, there’s this post as a result of it. This is in fact my 2 cents on the matter — and as such I’d recommend you read Nicolas’ point of view too […]

Small Note on gradle’s afterEvaluate

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If you use gradle and you took the path to write your own gradle plugins (try it, it’s fun!) to make your build process more … “enjoyable”, then this might come in handy one day. I have worked on a few gradle plugins, some of them inside the Netflix Nebula suite, some of them outside Netflix […]

Java Map and Subtleties of getOrDefault vs computeIfAbsent

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I wrote recently about the new niceties in the Map interface that Java 8 brought to light where I’m highlighting in particular 2 new methods: getOrDefault and computeIfAbsent (see my previous post here about it). These provide a cleaner (and as it turns out faster too!) way of retrieving values from a Map instance. However, […]