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.

  • Build Agents and Models on One Platform Icon
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  • 1
    Spring Cloud Examples

    Spring Cloud Examples

    Spring Cloud learning cases, service discovery, service governance

    The Spring Cloud Examples repository appears to be a collection of sample applications and demos that illustrate how to use Spring Cloud and related cloud-native patterns in real-world microservice or distributed-service contexts. It provides working codebases showing how to wire together service discovery, configuration, inter-service communication, and possibly resilience patterns — giving developers a hands-on playground rather than theoretical documentation. By studying the examples, one can understand how Spring Cloud works in practice: how to structure services, how to configure them, and how they interact under realistic conditions. For developers new to microservices or to Spring Cloud, this repo lowers the barrier to adoption by offering a ready-made baseline they can inspect, run, and modify. It can also function as a reference when designing architecture for a cloud-native backend, or as a starting point for a new microservices project.
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  • 2
    Spring Cloud Sleuth

    Spring Cloud Sleuth

    Distributed tracing for spring cloud

    Spring Cloud Sleuth provides Spring Boot auto-configuration for distributed tracing. Sleuth configures everything you need to get started. This includes where trace data (spans) are reported to, how many traces to keep (sampling), if remote fields (baggage) are sent, and which libraries are traced. Add Spring Cloud Sleuth to the classpath of a Spring Boot application (together with a Tracer implementation) and you will see trace IDs in logs.
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  • 3
    Spring Cloud Tutorial

    Spring Cloud Tutorial

    Spring Cloud Basics Tutorial, continuously updated

    SpringCloud-Learning is a tutorial repository containing runnable examples for building microservice systems with Spring Cloud. Its code is organized around several framework generations, including Brixton, Dalston, Edgware, and Finchley. The lessons cover service registration, discovery, client communication, distributed configuration, gateways, and fault tolerance. Additional examples explore message-driven services, distributed tracing, monitoring, retries, and API documentation. The repository also includes Spring Cloud Alibaba material for Nacos, Sentinel, and Dubbo integration. It is best suited to Java developers who want practical companion code for studying established Spring Cloud patterns across older release families.
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  • 4

    Spring Contributions

    Some spring-like modules

    This project is intented to host a few spring-like modules of my own.
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  • Fully Managed MySQL, PostgreSQL, and SQL Server Icon
    Fully Managed MySQL, PostgreSQL, and SQL Server

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  • 5
    Spring Hand Penetration Column

    Spring Hand Penetration Column

    Aims to learn Spring source code and understand principles of Spring

    Spring Hand Penetration Column is a hands-on Java learning project that teaches Spring internals by rebuilding a simplified Spring framework step by step. The repository breaks the framework into multiple learning stages so developers can understand each core concept through implementation rather than passive reading. It preserves key Spring ideas such as IoC, AOP, bean lifecycle, application context, scopes, resource loading, annotation configuration, and package scanning. Each step is designed to simplify the original Spring source code while retaining the logic that matters for understanding how the framework works. The project is especially useful for Java developers who find the full Spring source code too large or difficult to approach directly. It also connects implementation details with design patterns and architectural reasoning.
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  • 6
    Spring Integration

    Spring Integration

    Provides an extension of the Spring programming model

    Extends the Spring programming model to support the well-known Enterprise Integration Patterns. Spring Integration enables lightweight messaging within Spring-based applications and supports integration with external systems via declarative adapters. Those adapters provide a higher-level of abstraction over Spring’s support for remoting, messaging, and scheduling. Spring Integration’s primary goal is to provide a simple model for building enterprise integration solutions while maintaining the separation of concerns that is essential for producing maintainable, testable code.
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  • 7
    Spring PetClinic

    Spring PetClinic

    A sample Spring-based application

    The Spring Petclinic is the canonical reference sample application built with Spring Boot and Thymeleaf, demonstrating best practices in building Spring-based web applications; forks also exist showcasing implementations with modern architectures like microservices, reactive stacks, and AI integrations. In its default configuration, Petclinic uses an in-memory database (H2) which gets populated at startup with data. The h2 console is exposed and it is possible to inspect the content of the database using the jdbc:h2:mem:<uuid> URL. The UUID is printed at startup to the console. One of the best parts about working on the Spring Petclinic application is that we have the opportunity to work in direct contact with many Open Source projects.
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  • 8
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  • 9
    Persistence framework.
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  • Endpoint Management with Remote Control Built In Icon
    Endpoint Management with Remote Control Built In

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  • 10
    Staccato-Commons
    Staccato-Commons is a project that extends and integrates existing Java frameworks in order to fill gaps and unificate abstractions, focusing on productivity and maintainability, in a full OO way and using functional programming techniques.
    Downloads: 0 This Week
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  • 11
    Stagemonitor

    Stagemonitor

    An open source solution to application performance monitoring for java

    Stagemonitor is a Java monitoring agent that tightly integrates with time series databases like Elasticsearch, Graphite and InfluxDB to analyze graphed metrics and Kibana to analyze requests and call stacks. It includes preconfigured Grafana and Kibana dashboards that can be customized.
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  • 12
    A set of Java utility classes. ** This project has moved to BitBucket ** https://bitbucket.org/robeden/starlight-common
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  • 13
    StickyListHeaders

    StickyListHeaders

    An android library for section headers that stick to the top

    StickyListHeaders is an Android library that makes it easy to integrate section headers in your ListView. These section headers stick to the top like in the new People app of Android 4.0 Ice Cream Sandwich. This behavior is also found in lists with sections on iOS devices. This library can also be used without the sticky functionality if you just want section headers. StickyListHeaders actively supports android versions 2.3 (gingerbread) and above. That said, it works all the way down to 2.1 but is not actively tested or working perfectly. The goal of this project is to deliver a high performance replacement to ListView. You should with minimal effort and time be able to add section headers to a list. This should be done via a simple to use API without any special features. This library will always priorities general use cases over special ones. This means that the library will add very few public methods to the standard ListView and will not try to work for every use case.
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  • 14
    StoriesProgressView

    StoriesProgressView

    show horizontal progress like instagram stories.

    Library that shows horizontal progress like Instagram stories.
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  • 15

    StoryParser

    A set of tools and libraries to help with writing eBooks

    A set of tools and libraries (available for C# and Java) that help with writing fiction and non-fiction drafts and then produce ePUB and Kindle eBooks. With these tools/libraries, drafts, written in HTML, can be analyzed to help with writing. such as generating outlines and associating scenes with keywords. When done writing, the tools/libraries can be used to make publishable eBook, automatically producing additional material, such as Table of Contents and Title Pages.
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  • 16

    Struts Commons

    Interceptors and template classes for Struts 2 based applications

    Various template classes, interceptors and libraries used with Struts 6.7, including client written form field annotations, pagination, redirect after post, session per browser tab. See Javadoc.
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  • 17
    Subsampling Scale Image View

    Subsampling Scale Image View

    Deep zoom view for displaying huge images without loss of detail

    Android library (AAR). Highly configurable, easily extendable deep zoom view for displaying huge images without loss of detail. Perfect for photo galleries, maps, building plans etc. A custom image view for Android, designed for photo galleries and displaying huge images (e.g. maps and building plans) without OutOfMemoryErrors. Includes pinch to zoom, panning, rotation and animation support, and allows easy extension so you can add your own overlays and touch event detection. The view optionally uses subsampling and tiles to support very large images - a low resolution base layer is loaded and as you zoom in, it is overlaid with smaller high resolution tiles for the visible area. This avoids holding too much data in memory. It's ideal for displaying large images while allowing you to zoom in to the high resolution details. You can disable tiling for smaller images and when displaying a bitmap object.
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  • 18

    Super CSV

    A fast, programmer-friendly, free CSV library for Java

    Super CSV is a fast, programmer-friendly, open-source library for reading and writing CSV files with Java. PLEASE NOTE: As of January 2015 we have now moved to GitHub (https://github.com/super-csv/super-csv). This SourceForge page will remain, but with limited functionality (please go to GitHub to report issues and for project downloads). It is highly configurable, and supports reading and writing with POJOs, Maps and Lists. It also has support for deep-mapping and index-based mapping with POJOs, using the powerful Dozer extension. Its flexible 'Cell Processor' API automates data type conversions (parsing and formatting Dates, Integers, Booleans etc) and enforces constraints (mandatory columns, matching against regular expressions etc) - and it's easy to write your own if required. Super CSV is actively maintained, and the developers are ready and willing to help out if you get stuck :) Please check out the project website for examples and help getting started
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  • 19
    Another logging framework for Java. I try to balance flexibility, usabilty and performance using OOP. Currently the framework is usable but it lacks a lot of functionality.
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  • 20
    Surinam
    Surinam adds hyper-dynamic behavior to software by deploying and managing user-developed services that can come and go over time. This allows applications to be developed as loosely-coupled aggregations of services that can be modified in real time.
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  • 21
    Survey Developer Library 4 Java

    Survey Developer Library 4 Java

    Java framework with reusable patterns and classes

    A generic Java framework with reusable patterns and classes for enhanced development
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  • 22
    Sutsad is a library enabling functional programming in Java. It is based on commons-collections of Apache Commons.
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  • 23

    Swallow Project

    Libraries, utilities, and applications designed to simplify java

    Swallow project is a collection of libraries, utilities, and applications designed to simplify the java based developments.
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  • 24
    Java list implementation that swaps list items to a disk file in order to avoid out-of-memory error.
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  • 25
    Java generic Iterator implementation to generate permutations and combinations. Uses the algorithm described here http://en.wikipedia.org/wiki/Steinhaus%E2%80%93Johnson%E2%80%93Trotter_algorithm#Even.27s_speedup and the clear description of that algorithm here: http://www.cut-the-knot.org/Curriculum/Combinatorics/JohnsonTrotter.shtml
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