The magic will be some hand waving and performing the migration without changing a single line of code. The madness will be trying to figure out how it was done.

Quarkus is a  Java stack tailored for OpenJDK HotSpot (or OpenJ9 on zSeries) and GraalVM, crafted from optimized Java libraries and standards. It is a good choice for building highly-scalable applications while using lower amounts of CPU and memory resources than other Java frameworks. These applications can be traditional web applications, serverless applications, or even  functions as a service.

There are  many documented instances of organizations migrating their applications to Quarkus. In this article, let’s see one such migration path from  Spring Boot to Quarkus that is part magic and part madness! The magic will be some hand waving and performing the migration without changing a single line of code. The madness will be trying to figure out how it was done.

The Application

The application is a simple “to-do” task management system. The user can enter to-do items and then check them off once done. These items are stored in a  PostgreSQL database. All the application’s source code can be found here. There’s a version that uses  Gradle instead of  Maven as a build tool on the gradle branch.

Start the Database

The application requires a PostgreSQL database, so the first thing we will do is use Docker or  Podman to start an instance locally:

Shell

docker run --ulimit memlock=-1:-1 -it --rm=true --memory-swappiness=0 --name tododb -e POSTGRES_USER=todo -e POSTGRES_PASSWORD=todo -e POSTGRES_DB=tododb -p 5432:5432 postgres:11.5

#java #tutorial #spring #microservices #spring boot #migration #quarkus