Consumer Driven Contracts with Spring Cloud Contract

Jan 26 2017 Talk @ Toronto Java User Group

A video of my talk Consumer Driven Contracts with Spring Cloud Contract on Jan 26 2017 at the Toronto Java User Group.


Changing a published API over time is hard due to backward compatibility concerns. This is even more of an issue in a microservice architecture with 100’s of microservices that each publish and API. Consumer Driven Contracts is an effective service evolution pattern. In this talk we will explain the ideas behind Consumer Driven Contracts and show how to implement them easily with Spring Cloud Contract.

Spring Cloud Contract is an umbrella project holding solutions that help users in successfully implementing the Consumer Driven Contracts approach. Currently Spring Cloud Contract consists of the Spring Cloud Contract Verifier project.

Spring Cloud Contract Verifier is a tool that enables Consumer Driven Contract (CDC) development of JVM-based applications. It is shipped with Contract Definition Language (DSL) written in Groovy. Stating with version 1.1.0 you can define your own way of defining contracts – the only thing you have to provide is a converter. Contract definitions are used to produce following resources:

  • JSON stub definitions to be used by WireMock (HTTP Server Stub) when doing integration testing on the client code (client tests). Test code must still be written by hand, test data is produced by Spring Cloud Contract Verifier. Starting with version 1.1.0 you can provide your own implementation of the HTTP Server Stub.
  • Messaging routes if you’re using one. We’re integrating with Spring Integration, Spring Cloud Stream and Apache Camel. You can however set your own integrations if you want to.
  • Messaging routes if you’re using one. We’re integrating with Spring Integration, Spring Cloud Stream and Apache Camel. You can however set your own integrations if you want to.

Next Generation Session Management with Spring Session

Article I originally published at InfoQ, you can read the full version there.

Session management has been part of enterprise Java for so long that it has faded to the background of our consciousness as a solved problem, and we have not seen any major innovation in that arena in recent memory.

However the modern trend towards micro services and horizontally scalable cloud native applications challenges the assumptions upon which session managers have been designed and built for the past 20 years, and exposes flaws in the design of modern session managers.

This article will demonstrate how the recently released Spring Session APIs help surmount some of the limitations of the current approach to session management, traditionally employed by enterprise Java. We will start with a summary of the problems with current session managers, then dig into the details of how Spring Session solves each of those problems. We will wrap up the article with a detailed explanation of how Spring Session works and how you can use it in your projects.

Read the full article on InfoQ

Spring Framework 4 and Java 8

Article I originally published at InfoQ

Java 8 shipped with new language features and libraries and Spring 4.x is already supporting many of these. Some of the new Java 8 features don’t have an impact on Spring and can just be used as is, while other Java 8 features require Spring to explicitly support them. This article will walk you through the new Java 8 features that are supported by Spring 4.0 and 4.1.

Read full article at InfoQ.

Spring Boot Microservices

July 31 2014 Talk @ Toronto Java Users Group

Video of my talk Spring Boot Microservices on July 31 2014 at the Toronto Java Users Group.


According to Martin Fowler “The term “Microservice Architecture” has sprung up over the last few years to describe a particular way of designing software applications as suites of independently deployable services. While there is no precise definition of this architectural style, there are certain common characteristics around organization around business capability, automated deployment, intelligence in the endpoints, and decentralized control of languages and data.”

The presentation is going to explore the micro services architecture and how to implement micro services with spring boot. The presentation consists of a few slides and lot of live coding with Spring Boot. No previous Spring experience required to follow along the live coding