Apache Jakarta Regexp is a 100% pure Java regular expression package. Expression syntax supports all of Perl5 syntax, with the exception of back reference substitution markers (several people have mentioned this lack, so please feel free to contribute a solution). It also supports a very limited subset of POSIX features. Performance and features are somewhat inferior to ORO, and the new JDK 1.4 (java.util.regex) package, but the package is especially small and features the ability to precompile expressions (without using object serialization) into byte arrays, thus avoiding the need to load the expression compiler.
Expresso Framework is an open standards-based J2EE architectural framework that allows the developer to concentrate on application logic. It is a library of extensible Java Server application framework components for creating database-driven Web applications based on open standards. Expresso integrates with Apache Jakarta Struts, which emphasizes presentation and application configuration, and bringing a powerful tag library to Expresso. Expresso adds capabilities for security, robust object-relational mapping, background job handling and scheduling, self-tests, logging integration, automated table manipulation, database connection pooling, email connectivity, event notification, error handling, caching, internationalization, XML automation, testing, registration objects, configuration management, workflow, automatic database maintenance, and a JSP tag library.
Log4j is a logging package written in Java. Log4j allows you to log to a file, a java.io.Writer, a remote server, or a syslog daemon. The package is designed so that log statements can remain in shipped code without incurring a high performance cost. One distinctive feature of log4j is the notion of hierarchical loggers. Using hierarchical loggers, it is possible to select (at runtime) which log statements are output at arbitrary granularity. Users can choose to implement their own log formats and output strategies.
Velocity is a Java-based template engine. It permits anyone to use the simple yet powerful template language to reference objects defined in Java code. When Velocity is used for Web development, Web designers can work in parallel with Java programmers to develop Web sites according to the Model-View-Controller (MVC) model, meaning that Web page designers can focus solely on creating a site that looks good, and programmers can focus solely on writing top-notch code. Velocity separates Java code from the Web pages, making the web site more maintainable over the long run and providing a viable alternative to Java Server Pages (JSPs) or PHP. Velocity also provides template services for the Turbine Web application framework, making a template service that allows Web applications to be developed according to a true MVC model.
MX4J is an Open Source implementation of the JMX technology (JSR 3) and of the JMX Remote API (JSR 160). It aims to create JMX-related tools such as adaptors, connectors, and utility MBeans. JMX is the Java standard used to create manageable server-side applications, and it is used as a base architecture for many popular J2EE application servers, such as JBoss, BEA, Geronimo, etc.
miniLogger is a very small (4 classes and a 10KB jar) and easy to use logger. It uses a logging API that is a subset of JDK 1.4 logging but works on all Java 2 versions. It has been tested on Windows, Solaris, IRIX, and Linux for versions 1.2 and 1.3 of the Sun JDK. It supports logger control from the command line. Logger names are hierarchical separated by dots, and selecting any name automatically selects all names below. If logger_name is an empty string, it will affect all loggers. The loggers and level options are evaluated from left to right. It prints the thread name, source file name, and number line by default, and output can be redirected from System.err to file or any PrintStream. Finally, the logger hierarchy can easily mirror a package/class hierarchy or can be arbitrarily defined by the user.
Velosurf is a database mapping layer library for the Apache Velocity template engine. It provides automatic database mapping of tables and relationships without any code generation. In the context of a Webapp, it also provides handy tools for authentication, localization, and forms validation.