Even though interfaces and abstract classes have many similarities at first look, especially after introducing default methods, they have different use-cases and capabilities.

Java has multiple types for traversing elements of a source. My last article showed how java.util.Iterator<T> and java.util.ListIterator<T> can be used to traverse data structures like Collections. The concept of iterators is supported since Java 1.2, but got a new relative, java.util.Spliterator<T>, in Java 8.

Iterating data structures is one of the most common tasks. Everyone knows the classics, like for or while. But there are more ways to iterate in Java, providing a lot more functionality.

Dealing with date and time is a cumbersome task in many programming languages. But with Java 8, the JDK provides us with a comprehensive and completely new API, changing the way we deal with time-related concepts.

The three methods, map, filter, and reduce, are the cornerstone of any functional programming. Usually, our data pipelines consist of one or more intermediate operations, transforming (aka mapping) and/or filtering elements, and a terminal operation to gather the data again (aka reducing).

Java is often criticized as being too verbose. One aspect contributing to this characterization is the requirement to specify every type explicitly, which leads to a lot of additional noise. A new way of declaring local variables with less clutter was given to us with JDK 10 and JEP 286: local variable type inference.

We use java.util.Locale to format dates, numbers, currency, and more. But in some circumstances, these formatted strings have changed with JDK 9, leading to a multitude of subtle (and sometimes not so subtle) bugs.

I’m a great proponent of building our own tools. As developers, we perform many repetitive tasks, big and small. Many of these tasks might be made easier by using an appropriate tool instead. We often concentrate too much on solving more significant problems. Sometimes it doesn’t even need to be a real problem for a tool to be valuable. We have to find the sweet spots in our workflow.

Shell scripting is a powerful tool available on all platforms, even Windows, thanks to WSL. But it can be easy to make mistakes. Here are some tips to improve our scripts and avoid many problems.

In object-oriented languages, a nested or inner class is a class that’s completely declared within another class. This allows us to combine classes that are logically bound together, to increase encapsulation, for more concise and maintainable code. Here’s a quick, non-deep-dive overview of the 4 types of nested classes.