The Java Collections Framework is the recognised standard for collection handling in Java. Commons-Collections seek to build upon the JDK classes by providing new interfaces, implementations and utilities. There are many features, including:

• Bag interface for collections that have a number of copies of each object

• BidiMap interface for maps that can be looked up from value to key as well and key to value

• MapIterator interface to provide simple and quick iteration over maps

• Transforming decorators that alter each object as it is added to the collection

• Composite collections that make multiple collections look like one

• Ordered maps and sets that retain the order elements are added in, including an LRU based map

• Reference map that allows keys and/or values to be garbage collected under close control

• Many comparator implementations

• Many iterator implementations

• Adapter classes from array and enumerations to collections

• Utilities to test or create typical set-theory properties of collections such as union, intersection, and closure.

jsch-agent-proxy is a proxy program to OpenSSH's ssh-agent and Pageant included Putty. It will be easily integrated into JSch, and users will be allowed to use these programs for authentication.

Plexus-archiver contains a component to deal with project archives (jar).

ASM is an all purpose Java bytecode manipulation and analysis framework. It can be used to modify existing classes or dynamically generate classes, directly in binary form. The provided common transformations and analysis algorithms allow easily assembling custom complex transformations and code analysis tools.

Commons Math is a library of lightweight, self-contained mathematics and statistics components addressing the most common problems not available in the Java programming language or Commons Lang.

This package contains Jackson extension component for reading and writing XML encoded data.

Further, the goal is to emulate how JAXB data-binding works with "Code-first" approach (that is, no support is added for "Schema-first" approach). Support for JAXB annotations is provided by JAXB annotation module; this module provides low-level abstractions (JsonParser, JsonGenerator, JsonFactory) as well as small number of higher level overrides needed to make data-binding work.

The commons-pool package provides an object-pooling API and a number of object pool implementations. This package defines a handful of pooling interfaces and some base classes that may be useful when creating new pool implementations.

Bnd is a swiss army knife for OSGi, it creates manifest headers based on analyzing the class code, it verifies the project settings, it manages project dependencies, gives diffs jars, and much more.

ASM is an all purpose Java bytecode manipulation and analysis framework. It can be used to modify existing classes or dynamically generate classes, directly in binary form. The provided common transformations and analysis algorithms allow easily assembling custom complex transformations and code analysis tools.

This package provides the API module of the Log4j logging framework for Java.

EasyMock is a Java library that provides an easy way to use mock objects in unit testing.

ANTLR, ANother Tool for Language Recognition, (formerly PCCTS) is a language tool that provides a framework for constructing recognizers, compilers, and translators from grammatical descriptions containing Java, C#, C++, or Python actions. ANTLR provides excellent support for tree construction, tree walking, and translation.

This package provides a library of matcher objects (also known as constraints or predicates) allowing match rules to be defined declaratively, to be used in other frameworks. Typical scenarios include testing frameworks, mocking libraries and UI validation rules.

This package is the jaxb annotations module for jackson.

Eclipse LSP4J provides Java bindings for the Language Server Protocol and the Debug Adapter Protocol. This package is a common definition intended to be inherited by other packages.

ASM is an all purpose Java bytecode manipulation and analysis framework. It can be used to modify existing classes or dynamically generate classes, directly in binary form. The provided common transformations and analysis algorithms allow easily assembling custom complex transformations and code analysis tools.

MVEL has largely been inspired by Java syntax, but has some fundamental differences aimed at making it more efficient as an expression language, such as operators that directly support collection, array and string matching, as well as regular expressions. MVEL is used to evaluate expressions written using Java syntax.

In addition to the expression language, MVEL serves as a templating language for configuration and string construction.

OPS4J stands for Open Participation Software for Java. This package contains utilities and extensions related to handling streams and files.

Gson is a Java library that can be used to convert Java Objects into their JSON representation. It can also be used to convert a JSON string to an equivalent Java object. Gson can work with arbitrary Java objects including pre-existing objects that you do not have source-code of.

OSGi, for Open Services Gateway initiative framework, is a module system and service platform for the Java programming language. This package contains the log service.

Logback is intended as a successor to the popular log4j project. This module can be assimilated to a significantly improved version of log4j. Moreover, logback-classic natively implements the slf4j API so that you can readily switch back and forth between logback and other logging frameworks such as log4j or java.util.logging (JUL).

OpenJFX is a client application platform for desktop, mobile and embedded systems built on Java. Its goal is to produce a modern, efficient, and fully featured toolkit for developing rich client applications. This package contains base classes for the OpenJFX distribution and helper classes for building other parts of the distribution.

This package provides the Java development kit OpenJDK.

OPS4J stands for Open Participation Software for Java. This package contains utilities and extensions related to monitoring.