Another small, dependency-free library of ours is Pyranid - a minimalist JDBC interface for modern Java applications. It papers over the rough edges of the JDBC API so you can focus on writing SQL and mapping resultsets to Java objects. Bring your own dependency injector and have it create instances for you! A dead-simple API for transaction handling makes atomic operations a breeze, and of course you can specify isolation modes and rollback strategies.

We love libraries that follow the Unix philosophy - do one thing and do it well. Soklet is a minimalist, dependency-free Java 8 library in the spirit of Sinatra which lets you build powerful web applications and offers full control of request and response handling, should you need it.

It's designed to deeply integrate with your preferred DI library (we like Guice), has a "single zip" easy deployment with embedded Servlet container, and includes advanced features like static resource hashing and manifests.

Lokalized is a library that facilitates natural-sounding software translations. It features support for language form rule calculations (plural cardinality, ordinals, etc.) across 198 languages - the entire Unicode CLDR dataset! Unlike traditional solutions, it features a simple but powerful expression language which may be used by translators to handle traditionally-difficult edge cases.