Immutables allows you to embrace immutablity to tackle complexity and concurrency challenges. To get the benefits of immutability in Java, there's an annotation processor to easily create simple and consistent value objects. You can think of it as Guava's Immutable Collections but for regular objects. It includes support for JSON marshaling, MongoDB repositories, and JAX-RS.
Smooth Build is a build tool which provides a functional language which lets you describe a build process in a simple and readable way. A build script for a simple Java program can be as simple as "app.jar: files("src") | javac | jar;" All built artifacts are cached and indexed (hashed) using the sha1 of the expression (function name and its arguments) which returned a given artifact. This way, Smooth never builds the same artifact twice.
Variance provides a general-purpose, custom-wirable junction box for conversion between Java types. Values stored as Variants can be converted freely to any type (provided that a type converter exists between the original type and the target type), and users can add new type converters or override existing conversions.
owl2vcs is a set of tools designed to facilitate version control of OWL 2 ontologies using version control systems. It contains a commandline diff tool for OWL 2 ontologies integrated with Git and Mercurial. It detects axioms additions and removals, imports' additions and removals, ontology annotations' additions and removals, prefix additions, removals, modifications, and renames, ontology IRI and version IRI changes, and ontology format changes. It supports RDF/XML, OWL/XML, OWL Functional Syntax, Manchester OWL Syntax, and Turtle. It provides a changeset serializer and parser, two formats of changes, compact (like OWL Functional Syntax) and indented (the same, but more readable, using indents instead of parentheses), and four formats of IRIs: Simple, QName, Full, and Label.