OSGi is an open source specification that describes a modular system and a dynamic service platform for Java.
Application and component bundles can be remotely installed, started, stopped, updated, and uninstalled without requiring a reboot.
Quarkus is an open source, Kubernetes-native Java framework made for Java virtual machines and native compilation.
It optimizes Java specifically for containers, enabling it to become an effective platform for serverless, cloud, and Kubernetes environments.
Portlet is a technology for building web components to be placed on Web Portals. Vaadin provides the API to create a UI to be visible in Portlets in the same way as for a Vaadin Servlet-based application.