Let’s Make a Contract: The Art of Designing a Java API

An API is what developers use to achieve some task. More precisely it establishes a contract between them and the designers of the software exposing its services through that API. In this sense we’re all API designers: Our software…

Trade-offs in a Microservices Architecture

Is there an optimal software architecture? What does it look like? How do we measure ‘optimal’ when it comes to building and operating software? An optimal software architecture is one that has maximal flexibility for change at the lowest possible cost…

Learn to Love Your Legacy Code

What is a legacy system? It is old software that is very hard to maintain, to extend, and to improve. On the other hand, it is also a system that is working and is serving the business, otherwise it would not have survived.

Make Your Java Groovier

The screen was the color of an old cyberpunk novel, opened to the first page. I stared at it, head in my hands, worried I would never…

Keep Your Entity Mappings Simple and Efficient

JPA and Hibernate provide you with lots of complex mapping features. But you should better ignore them. Here is why…

The JVM is a Multiparadigm Platform: Use this to Improve your Programming

Java is an imperative language: Java programs tell the JVM what to do when. But computing is all about building abstractions. Java…

Threads Are Infrastructure, Treat them as Such

How many Java programmers manage — or even think about — stack use during their programming? More or less none. The vast majority of Java programmers leave stack management to the compiler and runtime system.

Let the Type System Work for You

In Java, types of variables are static (known at compile time) and manifest (explicitly named in source code). Some developers consider these attributes burdensome, leading to overly verbose code or an adversarial relationship with the compiler. Could they reap benefits…

Declarative Expression Is the Path to Parallelism

In the beginning, Java was an imperative, object-based programming language. Indeed, it still is. Over the years, though, Java has evolved, at each stage becoming more and more a language of declarative expression. Imperative is all about the…

Events Between Java Components

What is a component in Java?

One of the core concepts of object orientation in Java is that every class can be considered to be a component. Components can be extended or included to form bigger components. The final application is…