Free and Open Source, Distributed, RESTful Search Engine

Google core libraries for Java

ZXing ("Zebra Crossing") barcode scanning library for Java, Android

Apache Kafka - A distributed event streaming platform

a fast, scalable, multi-language and extensible build system

Desktop/Android/HTML5/iOS Java game development framework

Event bus for Android and Java that simplifies communication between Activities, Fragments, Threads, Services, etc. Less code, better quality.

Realm is a mobile database: a replacement for SQLite & ORMs

A Java API for generating .java source files.

A simple expressive web framework for java. Spark has a kotlin DSL https://github.com/perwendel/spark-kotlin

Hazelcast is a unified real-time data platform combining stream processing with a fast data store, allowing customers to act instantly on data-in-motion for real-time insights.

Apache Groovy: A powerful multi-faceted programming language for the JVM platform

Your go-to microservice framework for any situation, from the creator of Netty et al. You can build any type of microservice leveraging your favorite technologies, including gRPC, Thrift, Kotlin, R…

MapDB provides concurrent Maps, Sets and Queues backed by disk storage or off-heap-memory. It is a fast and easy to use embedded Java database engine.

Implementation of Instagram with Material Design (originally based on Emmanuel Pacamalan's concept)

OrientDB is the most versatile DBMS supporting Graph, Document, Reactive, Full-Text and Geospatial models in one Multi-Model product. OrientDB can run distributed (Multi-Master), supports SQL, ACID…

The Enterprise-ready testing and specification framework.

Hackpad is a web-based realtime wiki.

Java annotation processor to create immutable objects and builders, for records too. Sweep boilerplate code under the rug!

Repository that showcases 3 Android app architectures: "Standard Android", MVP and MVVM. The exact same app is built 3 times following the different patterns.

Deep Learning (Python, C, C++, Java, Scala, Go)

requery - modern SQL based query & persistence for Java / Kotlin / Android

Apache Parquet Java

DEPRECATED! Java implementation of the Ethereum yellowpaper. For JSON-RPC and other client features check Ethereum Harmony

Elasticsearch Java Rest Client.

🐘 Elasticsearch real-time search and analytics natively integrated with Hadoop

Embulk: Pluggable Bulk Data Loader.

Elassandra = Elasticsearch + Apache Cassandra

JPHP - an implementation of PHP on Java VM

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