Mbassador is a very lightweight message (event) bus implementation following the publish-subscribe pattern. It is designed for ease of use and aims to be feature rich and extensible while preserving resource efficiency and performance. It offers annotation-driven configuration (and thus imposes no structural dependencies into client code), synchronous and asynchronous message delivery (configurable for each message publication and listener), weak references to registered subscribers (no memory leaks possible), message filtering based on custom filters configured via annotations, clean error handling mechanisms, very high throughput, and strong support of concurrent access.
Easy I18N is a library that integrates GNU gettext with the JVM's internationalization facilities. Existing Java APIs (MessageFormat, DateFormat, Locale) are used to provide a much easier API for building and maintaining applications and Web apps. It includes the ability to use normal message strings in your code, use xgettext to auto-extract translatable strings, leverage the GNU gettext system and associated tools to manage translations, work with date, currency, and numeric input/output, supports thread-local Locales for Web apps (or global for apps), and more.