Struts 最初是 Jakarta项目中的一个子项目，并在2004年3月成为ASF的顶级项目。它通过采用 Java Servlet/JSP 技术，实现了基于Java EE Web应用的MVC设计模式的应用框架，是MVC经典设计模式中的一个经典产品
Velocity是一个基于java的模板引擎（template engine）。它允许任何人仅仅简单的使用模板语言（template language）来引用由java代码定义的对象。
simple API for presenting, processing and validating a command line interface.
a set of utilities and Java support classes for running Java applications as server processes.
a library of lightweight, self-contained mathematics and statistics components addressing the most common practical problems not immediately available in the Java programming language or commons-lang.
Simple encoder and decoders for various formats such as Base64 and Hexadecimal.
contains types that extend and augment the Java Collections Framework.
Provide an API for sending email. It is built on top of the JavaMail API, which it aims to simplify.
Apache Ignite is a horizontally scalable, fault-tolerant distributed in-memory computing platform for building real-time applications that can process terabytes of data with in-memory speed.
Defines an API for working with compression and archive formats. These include: bzip2, gzip, pack200, lzma, xz, Snappy, traditional Unix Compress, DEFLATE, DEFLATE64, LZ4, Brotli, Zstandard and ar, cpio, jar, tar, zip, dump, 7z, arj.
a simple yet flexible means of adding support for multipart file upload functionality to servlets and web applications
TinkerPop是一种开源图计算框架，既可用于联机事务处理（OLTP），又可用于联机分析处理系统（OLAP）。它可以用于处理单一机器以及分布式环境的庞大数据
Tools to assist in the reading of configuration/preferences files in various formats
