Stefano Cordio is a Lead Software Engineer at EPAM Systems and an open source enthusiast based in Zurich, Switzerland. He is an AssertJ maintainer, the Spring Batch Notion lead, and author of a few JUnit Framework extensions.

Beyond his own projects, Stefano actively contributes to the JUnit Framework and the Spring portfolio, and participates in open-source community events such as Hackergarten and Hack Commit Push.

GitHub: @scordio
BlueSky: @scordio.github.io
LinkedIn: @scordio
Mastodon: @scordio@mastodon.social
X: @stefanocodes

LOCATION: Zürich
ROOM: PH Zürich, Lagerstrasse 2, 8090 Zürich, Building LAB, Room F055, Travel instructions
KEYWORDS: Open Source, Testing, Tools

SPEAKER: Stefano Cordio   

AssertJ has been a player in Java testing for over a decade, providing an intuitive set of strongly typed assertions designed to maximize test readability. Since the launch of version 3.0, the library has undergone a massive expansion to support a wide range of use cases, specialized JDK types, and technologies like Guava and databases. However, this extended period of growth has resulted in a significant accumulation of technical debt and architectural friction that cannot be fully resolved while maintaining backward compatibility.

The transition to version 4 represents a great opportunity to address long-standing API inconsistencies and structural compromises. We can finally unify the API across various assertion styles and modules, streamline the implementation of third-party custom assertions, and elevate JVM languages like Kotlin and Groovy to first-class citizens. This release is not just about adding features; it is about refining the core engine to feel more native to the modern JVM ecosystem.

In this talk, we will candidly explore the "wrong" things, such as the technical debt and API inconsistencies accumulated over the 3.x era. We will see how AssertJ 4 is being built to eliminate friction for developers and meet the testing challenges of the next decade.

LANGUAGE: Talk: en / Slides: en

Stefano Cordio is a Lead Software Engineer at EPAM Systems and an open source enthusiast based in Zurich, Switzerland. He is an AssertJ maintainer, the Spring Batch Notion lead, and author of a few JUnit Framework extensions.

Beyond his own projects, Stefano actively contributes to the JUnit Framework and the Spring portfolio, and participates in open-source community events such as Hackergarten and Hack Commit Push.

GitHub: @scordio
BlueSky: @scordio.github.io
LinkedIn: @scordio
Mastodon: @scordio@mastodon.social
X: @stefanocodes

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