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.

  • Ship Agents Faster Icon
    Ship Agents Faster

    Transform your applications and workflows into powerful agentic systems at global scale.

    Gemini Enterprise Agent Platform lets you rapidly build, scale, govern and optimize production-ready agents grounded in your organization's data. The platform enables developers to build custom or pre-built agents for virtually any use case. New customers get $300 in free credits.
    Get Started Free
  • Save Up to 91% on Cloud Compute With Spot VMs Icon
    Save Up to 91% on Cloud Compute With Spot VMs

    Automatic sustained-use discounts. One free VM per month. No negotiation needed.

    Run batch jobs at 60-91% off with Spot VMs. Long-running workloads get automatic discounts with sustained use.
    Try Free
  • 1

    JavaGimmicks

    Utility classes, APIs and tools for Java

    A set of helper and utility classes, APIs and tools for the Java Programming Language. For more details - pleas visit the project homepage.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 2

    JavaJsonWrapping

    Simplified reading/writing/manipulation of Json with Java

    Downloads: 0 This Week
    Last Update:
    See Project
  • 3

    JavaLambdaCompose

    Utility methods for composing functional lambda expressions

    Provides for composing functional lambda instances to improve run-time efficiency and flexibility. The composition avoids excessive call stacking when processing multiple Predicate or Consumer instances, and can avoid the processing overhead of Collection.stream().filter().forEach() by replacing with Collection.forEach() using a composed Consumer from a Predicate and Consumer. Includes utility methods for composing an Iterable or array of Predicate instances into a single Predicate instance for testing for all, any, or none of the Predicate results. Includes utility methods for composing an Iterable or array of Consumer instances into a single Consumer instance. Includes utility methods for composing an Iterable or array of Predicate instances with an Iterable or array of Consumer instances into a single Consumer that tests for all, any, or none of the Predicate results. Includes a utility method for using streams to split a Collection according to comparators.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 4

    JavaMutex

    Provides 100% pure Java mutual exclusion.

    Freely redistributable open source 100% pure Java for mutual exclusion. Read-write and read-only reentrant lock, condition variable, atomic wraps for Boolean, Integer, Long, and Reference. Cell pool with optional locking, object exchanger, Intersect.
    Downloads: 0 This Week
    Last Update:
    See Project
  • $300 Free Credits for Your Google Cloud Projects Icon
    $300 Free Credits for Your Google Cloud Projects

    Start building on Google Cloud with $300 in free credits. No commitment, no credit card required until you're ready to scale.

    Launch your next project with $300 in free Google Cloud credits—no strings attached. Test, build, and deploy without risk. Use your credits across the entire Google Cloud platform to find what works best for your needs. After your credits are used, continue with always-free tier services. Only pay when you're ready to scale. Sign up in minutes and start exploring.
    Start Free Trial
  • 5
    Downloads: 0 This Week
    Last Update:
    See Project
  • 6
    JavaRTMP is a Java library for interacting with Adobe Flash Player and Adobe Air applications via the RTMP protocol
    Downloads: 0 This Week
    Last Update:
    See Project
  • 7
    JavaScript Object Graph for Java is a library designed to simplify working with JSON objects in Java code.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 8
    The Java Teamspeak 3 Server Query Software Development Kit is a Java Library that provides Classes to access the Teamspeak Server Query for easy integreating TSSQ into Java Desktop- or Web-Applications.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 9
    JavaTutorial

    JavaTutorial

    Ten years of experience as a veteran driver in Java technology

    Java Tutorial is a large Chinese-language knowledge base built from years of practical Java development experience. It connects core Java material with Java EE, web applications, servers, build systems, testing, monitoring, and deployment tools. The web section covers Servlets, JSP, filters, listeners, cookies, sessions, Tomcat, Jetty, and Nginx. Development tooling includes Maven, Ant, major IDEs, serializers, template engines, logging libraries, and testing utilities. Framework and middleware coverage includes MyBatis, Spring, Spring Boot, security tools, messaging systems, caches, and distributed services. The repository also links related tutorials and ebook pages, making it a navigable roadmap for learners and working Java engineers.
    Downloads: 0 This Week
    Last Update:
    See Project
  • MongoDB Atlas runs apps anywhere Icon
    MongoDB Atlas runs apps anywhere

    Deploy in 115+ regions with the modern database for every enterprise.

    MongoDB Atlas gives you the freedom to build and run modern applications anywhere—across AWS, Azure, and Google Cloud. With global availability in over 115 regions, Atlas lets you deploy close to your users, meet compliance needs, and scale with confidence across any geography.
    Start Free
  • 10
    Javaluator

    Javaluator

    A java infix evaluator based on "Shunting Yard" algorithm.

    Evaluate an arithmetic expression is as simple as: Double result = new DoubleEvaluator().evaluate("(e^3-1)*sin(pi/4)*ln(pi^2)"). But Javaluator provides you with much more ... Key features: - Functions support, including variable argument count. - Constants support: e, pi, etc ... - Variables support: Example sin(x) for x = pi/4. - Highly configurable: Reduce the built-in operator or function sets, define your own brackets. - Extensible: Define your own grammar, or extends the existing one. - Localizable: Define localized names for functions or constants. - Syntax check - Small footprint: 26kB, no additionnal library required. - Fully documented Please visit the project site to learn more : http://javaluator.fathzer.com If you use Javaluator in your product, we will be happy to add a link to your product in the Javaluator web site. Send an email to javaluator@fathzer.com. If you think Javaluator is valuable, vote up below.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 11
    Jaxil (Java XML interface library) is a project for connecting programs together.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 12
    Provides low level classes to facilitate the usage of JDBC and a basic persistence API with no reflection, no cast, thread safe less 'synchronized' blocks and the control of object allocations.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 13
    Jedi

    Jedi

    Java Enhanced Data Interface - Italian Senate Project

    JEDI is a J2EE application that provides a centralized service aiming at significantly simplify the generation of data driven documents in a enterprise environment. The documents (hereafter called "JEDI documents") can have different format types: pdf, excel, rtf, plain text data streams and xml streams. A JEDI document is an instance of the so called "managed document" (i.e. the configuration data and a particular set of rules), configured by a developer into the JEDI configuration database. The provision of a JEDI document is based on a synchronous processing performed by the JEDI core engine triggered by an end-user request (through HTTP request or RMI call). The content of a JEDI document (i.e. the input of the JEDI service), must be an XML stream regardless of the source. Such data is subsequently processed through one or more XSL transformations in order to provide the user with the document in the required format.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 14
    Jillion
    Java bio-informatics library to analyze and convert genomic sequence and assembly data. This library was created and used by the J. Craig Venter Institute (JCVI)
    Downloads: 0 This Week
    Last Update:
    See Project
  • 15
    A high-performance, fully extensible, RFC 854 Telnet client library and framework. Use it as a stand-alone end user client (making use of the JTerminal Swing component), or use the event-based API to automate host interactions. Supports VT100 TN3270
    Downloads: 0 This Week
    Last Update:
    See Project
  • 16

    Joda - Money

    Project moved to GitHub

    Joda-Money is a small library providing money and currency classes to complement Java 5 onwards. Project moved to GitHub: https://github.com/JodaOrg/joda-money
    Downloads: 0 This Week
    Last Update:
    See Project
  • 17
    This is a calendar widget based on the joda_time library. It will create customizable widget for the java platform. datefield, MonthPanel, calendarPanel are planned
    Downloads: 0 This Week
    Last Update:
    See Project
  • 18
    The Java Object Instance Security Toolkit
    Downloads: 0 This Week
    Last Update:
    See Project
  • 19
    Jollyday
    This API calculates the holidays for a given year, country and region or lets you provide your own holiday rules. Uses XML files for storing the holiday data. Uses JODA date/time API. Supports Europe, North/South America, Australia, Russia, India ...
    Downloads: 0 This Week
    Last Update:
    See Project
  • 20
    Joperties
    Joperties is an extension to the Properties class. It exists to solve a common problem with Properties (all Properties are Strings). Joperties allows you to set and get Java Objects without worrying about the transformation between String/Object.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 21

    Joplin I/O Library

    A Java Library for Improved I/O

    Joplin aims to provide improved I/O for the Java programming language. While the Java class library is extensive, its framework for performing complex I/O operations is missing several features, including comprehensive binary I/O. This notably includes classes for working with binary files, facilities for working with different encodings, and utilities for marshalling between Streams and NIO Channels.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 22
    Juffrou

    Juffrou

    Java Utilities Framework For the Rest Of Us

    Juffrou stands for Java Utilities Framework For the Rest Of Us and is a collection of useful classes or mini frameworks to help the java developer. Checkout the juffrou-reflect module if you are into performant java bean handling. There is also an xml marshaller / unmarshaller which is easy to use and has cool features like the Simplified Marshalling of nested beans.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 23
    A simple java library for JSON serialization.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 24
    Java utility classes that I've developed and want to carry from project to project without encumbrance. Others may find them useful. Releases are available from Maven Central: http://search.maven.org/#search%7Cga%7C1%7Cg%3A%22net.sf.kdgcommons%22
    Downloads: 0 This Week
    Last Update:
    See Project
  • 25

    KGJlib

    A Java library containing classes that I wrote and am happy to share.

    KGJlib is a Java library containing various different helper classes, etc. that I have written over the course of time. I open-sourced the library so that I could re-use it in any project I contribute to, and I'm developing it on SourceForge so that others can benefit from it too. The library contains useful classes for audio, JavaBeans, I/O operations, various type conversions, etc. One particularly interesting tool I developed is the NetSharedVariable system, which allows named variables (currently strings only) to be shared between different Java applications or apps that implement KGJlib on a single machine. Internally NetSharedVariable uses a client-server configuration, but that complexity is hidden from the application code which simply needs to interact with an instance of NetSharedVariable. JavaDocs and Wiki coming soon! KGJlib is Public Domain so that it can be used in proprietary projects without needing attribution, but if you use it I would love to here from you.
    Downloads: 0 This Week
    Last Update:
    See Project