Browse free open source Java Libraries and projects below. Use the toggles on the left to filter open source Java Libraries by OS, license, language, programming language, and project status.

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  • 1
    android-common-lib

    android-common-lib

    Android common lib, ImageCache, HttpCache, DropDownListView, etc.

    The Dev Tools App is a powerful android development tool that can help you improve efficiency greatly, It can be used to view the latest open source projects, view activity history, view manifest, decompile, color picker, extract apk or so, view app info, open or close the developer options quickly, and more. Includes cache (picture cache, prefetch cache, network cache), public View (drop down and load more ListView at the bottom, load more ScrollView at the bottom, slide a page Gallery) and common Android tools (network, download, Android resources) Operation, shell, file, Json, random number, Collection, etc.). You can choose a variety of cache algorithms (FIFO, LIFO, LRU, MRU, LFU, 13 types such as MFU) or custom caching algorithms. Cache can be initialized according to system configuration. Applicable to applications that get more pictures and frequently use pictures, including secondary cache, such as Sina Weibo, twitter, WeChat avatar, Meili Talk, Mogujie, Petal, Taobao, etc.
    Downloads: 1 This Week
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  • 2
    dnsjava

    dnsjava

    An implementation of the DNS protocol in Java

    dnsjava is an implementation of DNS in Java. It supports almost all defined record types (including the DNSSEC types), and unknown types. Can be used for queries, zone transfers, and dynamic updates. Includes a cache that can be used by clients, and an authoritative-only server. It supports TSIG authenticated messages, DNSSEC verification, and EDNS0.
    Downloads: 1 This Week
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  • 3
    jCasbin

    jCasbin

    An authorization library that supports access control models

    An authorization library that supports access control models like ACL, RBAC, ABAC for Golang, Java, C/C++, Node.js, Javascript, PHP, Laravel, Python, .NET (C#), Delphi, Rust, Ruby, Swift (Objective-C), Lua (OpenResty), Dart (Flutter) and Elixir. In Casbin, an access control model is abstracted into a CONF file based on the PERM metamodel (Policy, Effect, Request, Matchers). So switching or upgrading the authorization mechanism for a project is just as simple as modifying a configuration. Besides memory and file, Casbin policy can be stored into lots of places. Currently, dozens of databases are supported, from MySQL, Postgres, Oracle to MongoDB, Redis, Cassandra, AWS S3. jCasbin is a powerful and efficient open-source access control library for Java projects. It provides support for enforcing authorization based on various access control models.
    Downloads: 1 This Week
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  • 4
    jsoup

    jsoup

    Java library for working with real-world HTML

    jsoup is a Java library for working with real-world HTML. It provides a very convenient API for fetching URLs and extracting and manipulating data, using the best of HTML5 DOM methods and CSS selectors. jsoup implements the WHATWG HTML5 specification, and parses HTML to the same DOM as modern browsers do. jsoup is designed to deal with all varieties of HTML found in the wild; from pristine and validating, to invalid tag-soup; jsoup will create a sensible parse tree. The parser will make every attempt to create a clean parse from the HTML you provide, regardless of whether the HTML is well-formed or not. You have HTML in a Java String, and you want to parse that HTML to get at its contents, or to make sure it's well formed, or to modify it. The String may have come from user input, a file, or from the web.
    Downloads: 1 This Week
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    libsu

    libsu

    A complete solution for apps using root permissions

    libsu is a modern Android library that provides a safe, convenient API for executing commands with root privileges and interacting with the Android shell. Instead of ad-hoc Runtime.exec calls, it offers structured sessions, proper I/O streams, and lifecycle handling that works reliably across devices. The library focuses on developer ergonomics: thread-safe helpers, Kotlin-friendly APIs, and utilities for file operations, process management, and parcelable data transfer. It’s designed to interoperate smoothly with Magisk-based root environments while degrading gracefully on non-rooted devices when possible. Attention is given to security and correctness—avoiding resource leaks, handling timeouts, and containing elevated operations to explicit scopes. For apps that legitimately need privileged automation or maintenance tasks, libsu becomes the backbone that keeps the “root” parts predictable and testable.
    Downloads: 1 This Week
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  • 6
    ta4j

    ta4j

    A Java library for technical analysis

    Ta4j is an open-source Java library for technical analysis. It provides the basic components for the creation, evaluation, and execution of trading strategies. Ta4j is available on Maven Central. You can also download example code from the maven central repository. The wiki is the best place to start learning about ta4j. For more detailed questions, please use the issues tracker. We can calculate indicators over this bar series, in order to forecast the direction of prices through the study of past market data. Then we have to build our trading strategy. It is made of two trading rules, one for entry, the other for exit. Ta4j comes with a set of basic trading rules/strategies which can be combined using boolean operators. Trading strategies can be easily compared according to a set of analysis criteria. Ta4j can also be used for live trading with more complicated strategies.
    Downloads: 1 This Week
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  • 7

    eBus

    Publish/Subscribe, Request/Reply Messaging API for Java.

    A Java middleware API supporting broker-less, type+topic-based publish/subscribe and request/reply messaging for both intra- and inter-application, object-level communication. Broker-less: messages are transmitted directly between eBus applications. There is no message broker (i.e. server) in between. Type+topic addressing: eBus clients subscribe to a message class (type) and message topic, providing stronger typing than just topic-based subscriptions. Object-level communication: eBus delivers messages directly to client objects, not to a client process.
    Downloads: 9 This Week
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  • 8
    The JAVE (Java Audio Video Encoder) library is Java wrapper on the ffmpeg project. Developers can take take advantage of JAVE to transcode audio and video files from a format to another (
    Downloads: 8 This Week
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  • 9

    JEditor

    a simple Java text Editor with syntax highlighting which is designed t

    JEditor is a simple Java text Editor with syntax highlighting which is designed to be used in a library in other applications. A typical use case is an application which needs to edit text files.
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    Downloads: 8 This Week
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  • 10
    GLPK for Java

    GLPK for Java

    Java language binding for the GNU Linear Programming Kit (GLPK)

    GLPK for Java provides a Java language binding for the library GLPK. GLPK is a proven solver for linear and mixed integer mathematical programming problems. For Windows binaries see project GLPK for Windows (http://sourceforge.net/projects/winglpk/).
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    Downloads: 13 This Week
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  • 11
    silvertunnel - Java lib+browser for TOR
    silvertunnel.org is a project that provides an end-user browser, a Java library and additional Java security tools to easily access anonymity networks such as the Tor (torproject.org) network. Secure and easy to use. Tor4Java and Tor Browser. Attention: see project status on page https://sourceforge.net/p/silvertunnel/discussion/962278/thread/83dc2d02/#
    Downloads: 4 This Week
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  • 12
    G4P

    G4P

    GUI controls for Processing

    This project is about developing a set of 2D GUI controls for the Processing language. V4.2 is compatible with Processing 3 V3.5.4 is the last version compatible with Processing 2.
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    Downloads: 11 This Week
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  • 13
    GeoAPI

    GeoAPI

    Set of Java interfaces for geospatial applications

    The development community in building GIS solutions is sustaining an enormous level of effort. The GeoAPI project aims to reduce duplication and increase interoperability by providing neutral, interface-only APIs derived from OGC/ISO Standards.
    Downloads: 2 This Week
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  • 14

    Java-Arduino Communication Library

    Serial Communication between Java and Arduino made simple.

    Serial Communication between Arduino and Java has never been simpler. A better alternative to the RXTX library, the JavaArduinoLibrary is an easy to use library with simple methods that allow you, the JAVA programmer, to read and write from the serial port. Seamless serial communication with the port of your choice. Consists of a class that extends the JComboBox to provide a list of all available ports for selection. Overloaded functions for serialWrite() and serialRead() allow multiple methods of communication. Overloaded constructors and getter and setter methods expand the use case to any scenario. **IMPORTANT**: please download and import both JARs in the files into your project.
    Downloads: 7 This Week
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  • 15
    Voikko

    Voikko

    Library of linguistic tools

    Voikko is a spell checking, grammar checking, morphological analysis and hyphenation system. Spell checkers are available for multiple languages, other features for Finnish only.
    Downloads: 7 This Week
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  • 16
    An open source Java implementation to interpret and render Computer Graphics Metafile (CGM) graphics files.
    Downloads: 3 This Week
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  • 17
    ebfformat

    ebfformat

    An Efficient Binary data Format

    EBF, which stands for Efficient Binary Format, is a binary file format for reading and writing binary data easily. Reading writing routines are currently available in C,C++,Fortran,Java, Python, IDL, MATLAB. A program called ebftkpy which has a set of utility functions to work with the .ebf files , e.g., viewing the contents and getting a summary, is also provided. The EBF specification is designed to be concise and easy to understand to make it easier for others to write their own code if needed. It is also designed to simplify the programming of input output routines in different programming languages. In a nutshell an EBF file is a collection of data objects. Each data object is specified by a unique name and a single file can have multiple data objects. Each data object is preceded by a meta-data or header which describes the binary data associated with it. Among other things, this header allows the files to be portable across systems with different endianess.
    Downloads: 5 This Week
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  • 18

    UnboundID LDAP SDK for Java

    A Java-based LDAP API

    A fast, comprehensive, and easy-to-use Java API for communicating with LDAP directory servers and performing related tasks like reading and writing LDIF, encoding and decoding data using base64 and ASN.1 BER, and performing secure communication.
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    Downloads: 1 This Week
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  • 19
    A Java library for executing, parsing and persisting NMap output.
    Downloads: 1 This Week
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  • 20
    JDAL (Java Database Application Library)

    JDAL (Java Database Application Library)

    Java data access and swing binding library

    JDAL is a Java library that aims to help developers making database applications easily using Spring Framework and Hibernate, JPA or IBatis ORMs. Support generic DAOs and ready to use UI Components with server side pagination and sorting.
    Downloads: 4 This Week
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  • 21
    A Java library for creation and editing of several playlist formats.
    Downloads: 4 This Week
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  • 22
    NestProfessor Programmer Edition
    This is a SDK which can nest/layout the part/geometry/polygon on the material or sheet intelligently, you can get the best utilization of the materials, this SDK also support read/write DXF/DWG files and part-in-part nesting. New nesting lagorithm is implenmented, more good to support true shape part or material.
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    Downloads: 2 This Week
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  • 23

    WITSML client

    ****** NOTE: This software is outdated! ******

    ****** NOTE: This software is outdated! You should use software implementing the latest versions of the WITSML standard. See http://www.witsml.org/ and http://www.jwitsml.org for more info ****** This is an SDK for developing WITSML Java clients (version 1.2, 1.3, and 1.4). The code contains everything you need to easily connect and retrieve data from a WITSML server. More information (tutorial etc) can be found here: http://www.jwitsml.org
    Downloads: 2 This Week
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  • 24
    Graphane is a solution to generate and deliver enterprise documents (PDF, ODT, RTF, HTML). Templates documents are designed with OpenOffice Writer. Any application being able to export data in XML format can submit these data to the Graphane Server.
    Downloads: 3 This Week
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  • 25

    RELATED - REmotes LAboraTories extenED

    Java Framework for developing of remote/virtual laboratories

    RELATED framework proposes a structured methodology of remote/virtual labs development and, also, provides common facilities as user management, booking, basic visualization (trend graphs and direct interaction using interactives variables), data logging and experimental session’s control. In order to get these facilities, an RLAB (Remote LABoratory) system it defined using a formal specification of a virtual or remote laboratory (based on XML and used to structure components for laboratory). The main component is experiment, so students could run these experiments using RELATED facilities as painting data from the laboratory, change any relevant variable or take a look on laboratory structure. In order to integrate a laboratory as an RLAB system, the researchers and lecturers only have to develop local access to equipment using Java technology, using the “module” paradigm.
    Downloads: 3 This Week
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