VRaptor3 is a fully-fledged Java Web framework focused on fast development and maintainable code. It intends to make RESTful application development easy. A resource corresponds to a business logic annotated with its path and HTTP method. It runs inside DI Containers (Spring or Pico out of the box) and, therefore, enables full integration with them. Also, using Hibernate is easier: its session is automatically injected by VRaptor, so you just have to use it. VRaptor3 is refactor-friendly, especially in its redirecting configuration. It is also nicely extensible.
HornetQ is a multi-protocol, embeddable, high performance, clustered, asynchronous messaging system. HornetQ is an example of Message Oriented Middleware. It includes an extensive, easy-to-understand user-manual and quick-start guide and over 65 ready-to-run examples out of the box, demonstrating everything from simple JMS usage to complex clusters of servers and more exotic functionality. Its elegant POJO based design has minimal third party dependencies. You can run HornetQ as a stand-alone messaging broker, run it in integrated in your favorite JEE application server, or run it embedded inside your own application. Its journal provides high persistent messaging performance. Automatically switching into native mode when running on Linux, it uses asynchronous IO to provide persistent messaging rates that can saturate the write throughput of a disk. Its pluggable transport system uses JBoss Netty out of the box to provide high performance and scalability on the wire.
Thread Weaver is a framework for writing multithreaded unit tests for Java classes. It lets you create breakpoints inside your code and to stop individual threads when they reach a breakpoint. This allows you to produce controlled repeatable tests that can help to verify thread safety and detect race conditions.
Niocchi is a Java crawler library implementing synchronous I/O multiplexing. This specific type of implementation allows crawling tens of thousands of hosts in parallel on a single low end server. Niocchi has been designed for big search engines that need to crawl massive amount of data, but can also be used to write no-frills crawlers.
lambdaj is a Java library that allows you to manipulate collections in a pseudo-functional and statically typed way. The main purpose of lambdaj is to partially eliminate the burden of writing (often nested and poorly readable) loops while iterating over collections. In particular, it allows you to iterate a collection in order to filter its items on a given condition, convert each item with a given rule, extract a given property from each item, sort the items on the values of one of their properties, group or index the items on the value of one or more properties, invoke a method on each item, or aggregate the items or the values of one of their properties. It allows all this without having to write a single explicit loop.
treap.py is a treap implementation for Python. A treap is a hybrid of a binary tree and a binary heap that is self-balancing and is O(nlog2(n)) for most operations, including deleting a value, inserting a value, finding the least value, and finding the greatest value. This particular treap implementation looks like a dictionary to the caller, but it also supports getting an ordered list (forward or reverse) in O(n) time. The code is available as pure Python (should run on about any Python implementation supporting generators, but was tested on CPython 2.6) or as part Python and part Cython for performance. The version with Cython should run on CPython or Unladen Swallow, but was only tested on CPython 2.6.