QuestDB is a high performance, open-source, time-series database

Vert.x is a tool-kit for building reactive applications on the JVM

The world's fastest open query engine for sub-second analytics both on and off the data lakehouse. With the flexibility to support nearly any scenario, StarRocks provides best-in-class performance …

Micronaut Application Framework

Apache Ignite

Generates a unified GraphQL schema from gRPC microservices and other Protobuf sources

An example approach for implementing a Clean/Hexagonal Architecture

Spring 5/6 Reactive playground

Infinispan is an open source data grid platform and highly scalable NoSQL cloud data store.

Elide is a Java library that lets you stand up a GraphQL/JSON-API web service with minimal effort.

Apache XTable (incubating) is a cross-table converter for lakehouse table formats that facilitates interoperability across data processing systems and query engines.

Kafka Examples focusing on Producer, Consumer, KStreams, KTable, Global KTable using Spring, Kafka Cluster Setup & Monitoring. Implementing Event Sourcing and CQRS Design Pattern using Kafka