io-util is a small, scalable Java library for slicing and dicing fixed width tables on disk. The objective is to provide reusable blocks of code for building efficient, custom binary data stores. It allows you to build, search, and maintain a large, externally stored, fixed width, sorted table. The library user specifies the row width (in bytes), a row comparison function (which implicitly defines any given row's key), and an optional delete codec.
J2ObjC is a tool from Google that translates Java code to Objective-C for the iOS platform. It enables Java code to be part of an iOS build, as no editing of the generated files is necessary. The goal is to write an app's non-UI code (such as data access or application logic) in Java, which can then be shared by Web apps using GWT, Android apps, and iOS apps. J2ObjC supports most Java language and runtime features required by client-side application developers, including exceptions, inner and anonymous classes, generic types, threads, and reflection. JUnit test translation and execution are also supported.
jGetFile is a scriptable commandline recursive file downloader for the Web. It handles many of the HREF configurations not supported in other mass downloaders, such as embedded URLs in parameters. It also supports a highly configurable means to filter the acceptance of links within the program.
jOOX stands for Java Object Oriented XML. It is a simple wrapper for the org.w3c.dom package to allow for fluent XML document creation and manipulation where DOM is required but too verbose. jOOX only wraps the underlying document and can be used to enhance DOM, not as an alternative. It is inspired by jOOQ and jQuery.
jSai is a servlet authentication implementation which aims to allow easier to use, more powerful authentication for Java servlets. It is aimed at servlet developers who want more than the servlet spec, but not as much as a full Enterprise Server. It provides a powerful set of authentication and authorization features for user level security in servlet-based Web applications.