The Java Stream API has many useful methods. If we want to transform a Stream to a Java array we can use the toArray method. Without an argument the result is an object array (Object[]), but we can also use an argument to return an array of another type. The easiest way is to use the contructor of the array type we want as method reference. Then the result is an array of the given type with the elements of the stream.

This is very useful if we have a Java Stream and want to use the elements to invoke a method with a variable arguments parameter. In Java we can pass an array object as variable arguments argument to a method. So if we transform the Stream to an array we can invoke the method with that value.

One of the first topics you will encounter when studying functional programming will probably be currying. For an imperative programmer not used to mathematical notations, chances are you will find the concept hard to grasp. Then let this be the day you will remember as the day you completely understood currying!

When you maintain a large Java project for a longer period, the moments where you’re finally able to remove unused code can be very satisfying. No more upkeep, library version migrations or dark corners to maintain, for code that’s no longer being used. But finding out which parts of the code base can be removed can be a challenge, and tooling in this space seems not to have kept pace with recent development practices in Java. In this post we’ll outline an approach to find unreferenced code with ArchUnit, which allows you to iteratively detect & delete unused code from your Java projects.

The Optional class has the orElse and orElseGet methods to return a value when the Optional object is empty. This is useful to return a default value for example. But there is a small difference between the two methods. The orElseGet method needs a Supplier argument that returns a value of the type of the Optional value. The Supplier is only invoked when the Optional value is empty. The statement passed as argument to the orElse method is always executed, even when the Optional value is not empty. Preferrably we should use orElseGet as it will only invoke statements if needed.

In the following example code we see when our method getDefaultGreeting is invoked by using orElse and orElseGet with an empty and non-empty Optional object:

Since I’ve been working on a Mac, I replaced the default terminal with iTerm2. It provides some nice features like searching, autocomplete, or allowing to see images in the terminal. But this one is my favorite one, the undo close tab / session.

Many projects force their code to be formatted. We use spotless for this purpose. It can check for propper formatting, and also format the code for you. Then build pipeline checks if the code is properly formatted. Failing pipelines due to formatting errors are annoying and cost a lot of time and money. This blog proposes a solution.

Welcome back to the final blog in de series "How to hack a box"! In this blog we’ll cover the basics of Privilege Escalation and see it in practice on the Blocky box from Hack The Box.

Welcome back to the blog series about how to hack a box! In the past few blogs we’ve gone through a few steps which gives you an idea of how you can hack a box. We went from the Introduction, to Exploration, to Gaining Access. In this blog, we’ll cover the basics of Enumeration.

The time is right. Your work is done. The last letter of your Java code has been written. You let the IDE compile the code and a new running version of your app is ready to be released. You’ve done this a thousand times, there’s nothing new on the horizon. The question of what lies beneath, what happens under the hood, has never occurred to you. Until now!

When code evolves we usually deprecate old code. Sometimes we come across deprecations without any hints with what to replace it with. Kotlin has a solution for this by allowing you to specify a replace instruction.

For example, we created have an old REST client.