The Most Widely Used Java Libraries

Update on 2020/10/07: This list was created nearly 10 years ago. The new list is available here.

This article summarizes the most popular and widely used Java libraries for a variety of different applications.

1. Core

  • Apache Commons Lang – Apache’s library that provides a host of helper utilities for the java.lang API, such as String manipulation, object creation, etc.
  • Google Guava – Google’s Core library for collections, caching, primitives support, etc. (example)

2. HTML, XML Parser

  • Jsoup – a convenient library to manipulate HTML. (example)
  • STaX – Process XML code. (example)

3. Web Frameworks

  • Spring – an open source application framework and inversion of control container for the Java platform. (example)
  • Struts 2 – most popular web framework from Apache. (example)
  • Google Web Toolkit – a development toolkit from Google for building and optimizing complex browser-based applications. (example)
  • Strips – a presentation framework for building web applications using the latest Java technologies.
  • Tapestry – component oriented framework for creating dynamic, robust, highly scalable web applications in Java.
  • Here is a comparison of those frameworks.

4. Chart, Report, Graph

  • JFreeChart – creates charts such as bar charts, line charts, pie charts, etc.
  • JFreeReport – creates PDF reports.
  • JGraphT – create graph that contains a set of nodes connected by edges.

5. Windowing Libraries

6. GUI Frameworks

7. Natural Language Processing

  • OpenNLP – a library from Apache. (example)
  • Stanford Parser – a library from Stanford University. (example)

If you are an expert of NLP, here are more tools.

8. Static Analysis

  • Eclipse JDT – a library from IBM which can manipulate Java source code. (example)
  • WALA – a library that can process .jar file, i.e., bytecode. (example)

9. JSON

  • Jackson – a multi-purpose Java library for processing JSON data format. Jackson aims to be the best possible combination of fast, correct, lightweight, and ergonomic for developers.
  • XStream – a simple library to serialize objects to XML and back again.
  • Google Gson – a Java library that can be used to convert Java Objects into their JSON representation. (example)
  • JSON-lib – a java library for transforming beans, maps, collections, java arrays and XML to JSON and back again to beans and DynaBeans.

10. Math

  • Apache Commons Math – provide functions for math and statistics.

11. Logging

  • Apache Log4j – most popular logging library. (example)
  • Logback – a successor to the popular log4j project.
  • The Simple Logging Facade for Java (SLF4J) – a simple facade or abstraction for various logging frameworks (e.g. java.util.logging, logback, log4j) allowing the end user to plug in the desired logging framework at deployment time.

12. Office-Complicant

  • Apache POI – APIs for manipulating various file formats based upon Microsoft’s OLE 2 Compound Document format using pure Java.
  • Docx4j – a Java library for creating and manipulating Microsoft Open XML (Word docx, Powerpoint pptx, and Excel xlsx) files.

— More from comments —

13. Date and Time

  • Joda-Time – a quality replacement for the Java date and time classes.

14. Database

  • Hibernate / EclipseLink / JPA
  • JDO
  • jOOQ
  • SpringJDBC / Spring Data
  • Apache DbUtils

Development Tools

  • Lombok – a Java library meant to simplify the development of Java code writing

* 1) The list above are based on my own survey combined with personal experience. It is possible that they are not precisely THE MOST popular, but at least well-known.
* 2) I will keep updating this list to make it more complete and accurate. Thanks for your comments.

18 thoughts on “The Most Widely Used Java Libraries”

  1. How about listing a couple of database libraries? These come to mind:
    – Hibernate / EclipseLink / JPA
    – JDO
    – jOOQ
    – SpringJDBC / Spring Data
    – Apache DbUtils

  2. Just curious – what is your reference for writing “most popular web framework from Apache” for Struts 2 – I would have thought Spring Web MVC is now the most popular (most used) web framework.

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