News could hardly get more exciting than this, for a programming language aficionado! There is now a JEP 286 for Local-Variable Type Inference with status "Candidate". And a request for feedback by Brian Goetz, which I would love to invite you to participate in: http://mail.openjdk.java.net/pipermail/platform-jep-discuss/2016-March/000037.html Please do so, the survey remains open only from March … Continue reading Java 10’s new Local-Variable Type Inference
Category: java 8
How to Support Java 6, 8, 9 in a Single API
With jOOQ 3.7, we have finally added formal support for Java 8 features. This opened the door to a lot of nice improvements, such as: Creating result streams try (Stream<Record2<String, String>> stream = DSL.using(configuration) .select(FIRST_NAME, LAST_NAME) .from(PERSON) .stream()) { List<String> people = stream.map(p -> p.value1() + " " + p.value2()) .collect(Collectors.toList()); } Calling statements asynchronously … Continue reading How to Support Java 6, 8, 9 in a Single API
(Ab)using Java 8 FunctionalInterfaces as Local Methods
If you're programming in more advanced languages like Scala or Ceylon, or even JavaScript, "nested functions" or "local functions" are a very common idiom to you. For instance, you'll write things like fibonacci functions as such: def f() = { def g() = "a string!" g() + "– says g" } (Question from Stack Overflow … Continue reading (Ab)using Java 8 FunctionalInterfaces as Local Methods
The Mute Design Pattern
Have you been writing a lot of code following the Mute-Design-Pattern™ lately? E.g. try { complex(); logic(); here(); } catch (Exception ignore) { // Will never happen hehe System.exit(-1); } There's an easier way with Java 8! Just add this very useful tool to your Utilities or Helper class: public class Helper { // 18395 … Continue reading The Mute Design Pattern
An Ingenious Workaround to Emulate an Application of Union Types in Java
Before I move on with the actual article, I'd like to give credit to Daniel Dietrich, author of the awesome vavr library, who has had the idea before me: https://twitter.com/danieldietrich/status/699633269202149377 Contravariant Generic Bounds It all started with a tweet: https://twitter.com/lukaseder/status/699588908095508480 I wanted to do something like pattern-matching a common super type of a set of … Continue reading An Ingenious Workaround to Emulate an Application of Union Types in Java
Using Oracle AQ via Java 8 Streams
One of the most awesome features of the Oracle database is Oracle AQ: Oracle Database Advanced Queuing. The AQ API implements a full fledged, transactional messaging system directly in the database. In a classic architecture where the database is at the center of your system, with multiple applications (some of which written in Java, others … Continue reading Using Oracle AQ via Java 8 Streams
How to Pattern-Match Files and Display Adjacent Lines in Java
Recently, we've published our article about the awesome window function support in jOOλ 0.9.9, which I believe is some of the best additions to the library that we've ever done. Today, we'll look into an awesome application of window functions in a use-case that is inspired by this Stack Overflow question Sean Nguyen: How to … Continue reading How to Pattern-Match Files and Display Adjacent Lines in Java
Use JUnit’s expected exceptions sparingly
Sometimes, when we get pull requests for jOOQ or our other libraries, people change the code in our unit tests to be more "idiomatic JUnit". In particular, this means that they tend to change this (admittedly not so pretty code): @Test public void testValueOfIntInvalid() { try { ubyte((UByte.MIN_VALUE) - 1); fail(); } catch (NumberFormatException e) … Continue reading Use JUnit’s expected exceptions sparingly
2016 Will be the Year Remembered as When Java Finally Had Window Functions!
You heard right. Up until now, the awesome window functions were a feature uniquely reserved to SQL. Even sophisticated functional programming languages still seem to lack this beautiful functionality (correct me if I'm wrong, Haskell folks). We've written tons of blog posts about window functions, evangelising them to our audience, in articles like: Probably the … Continue reading 2016 Will be the Year Remembered as When Java Finally Had Window Functions!
3 Reasons why You Shouldn’t Replace Your for-loops by Stream.forEach()
Awesome! We're migrating our code base to Java 8. We'll replace everything by functions. Throw out design patterns. Remove object orientation. Right! Let's go! Wait a minute Java 8 has been out for over a year now, and the thrill has gone back to day-to-day business. A non-representative study executed by baeldung.com from May 2015 … Continue reading 3 Reasons why You Shouldn’t Replace Your for-loops by Stream.forEach()