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

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  • 1
    Technical analysis library with indicators like ADX, MACD, RSI, Stochastic and TRIX, plus candlestick pattern recognition. Docs: https://ta-lib.org Available natively in C/C++, Java, Rust and C# with wrappers for python, R and many other ecosystems. MOVED TO GITHUB: https://github.com/TA-Lib/ta-lib . No further support is provided on SourceForge. Release 0.4.0 is very outdated, please check github for the most recent release.
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    Downloads: 5,603 This Week
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  • 2
    Arduino

    Arduino

    Open-source electronics platform

    Arduino is an open-source physical computing platform based on a simple I/O board and a development environment that implements the Processing/Wiring language. Arduino can be used to develop stand-alone interactive objects or can be connected to software on your computer (e.g. Flash, Processing and MaxMSP). The boards can be assembled by hand or purchased preassembled. Arduino is a popular tool for IoT product development as well as one of the most successful tools for STEM/STEAM education. Hundreds of thousands of designers, engineers, students, developers and makers around the world are using Arduino to innovate in music, games, toys, smart homes, farming, autonomous vehicles, and more. Arduino is the first widespread Open Source Hardware project and was set up to build a community that could help spread the use of the tool and benefit from contributions from hundreds of people who helped debug the code, write examples, create tutorials, etc.
    Downloads: 154 This Week
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  • 3
    MOA - Massive Online Analysis

    MOA - Massive Online Analysis

    Big Data Stream Analytics Framework.

    A framework for learning from a continuous supply of examples, a data stream. Includes classification, regression, clustering, outlier detection and recommender systems. Related to the WEKA project, also written in Java, while scaling to adaptive large scale machine learning.
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    Downloads: 298 This Week
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  • 4
    JavaBlock
    Free Java Flowchart simulator / interpreter
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    Downloads: 769 This Week
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    Hello Algorithm

    Hello Algorithm

    Animated illustrations, one-click data structure

    Animated illustrations, one-click data structure and algorithm tutorials. This project aims to create an open source, free, novice-friendly introductory tutorial on data structures and algorithms. The whole book uses animated illustrations, the content is clear and easy to understand, and the learning curve is smooth, guiding beginners to explore the knowledge map of data structures and algorithms. The source code can be run with one click, helping readers improve their programming skills during exercises and understand the working principles of algorithms and the underlying implementation of data structures. Readers are encouraged to help each other learn, and questions and comments can usually be answered within two days.
    Downloads: 9 This Week
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  • 6
    jsprit

    jsprit

    Open source toolkit for solving rich vehicle routing problems

    jsprit is a java based, open-source toolkit for solving rich Traveling Salesman Problems(TSP) and Vehicle Routing Problems(VRP). It is lightweight, flexible and easy-to-use, and based on a single all-purpose meta-heuristic. Setting up the problem, defining additional constraints, modifying the algorithms and visualizing the discovered solutions is as easy and handy as reading classical VRP instances to benchmark your algorithm. It is fit for change and extension due to its modular design and a comprehensive set of unit and integration tests. Possibility to define additional stateless and stateful constraints/conditions to account for the richness of your problem. GraphHopper invests in an active open source community. Our flagships are the GraphHopper routing engine and jsprit, the toolkit for solving rich vehicle routing problems. We promote a fair & diverse mindset.
    Downloads: 9 This Week
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  • 7
    JoSQL (Java Objects SQL) provides SQL capabilities for querying, ordering and grouping of collections of Java objects (POJOs). It allows a SQL statement to be applied to the collection of objects and the matching set returned, ordered and grouped.
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    Downloads: 122 This Week
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  • 8
    java-string-similarity

    java-string-similarity

    Implementation of various string similarity and distance algorithms

    Implementation of various string similarity and distance algorithms: Levenshtein, Jaro-winkler, n-Gram, Q-Gram, Jaccard index, Longest Common Subsequence edit distance, cosine similarity. A library implementing different string similarity and distance measures. A dozen of algorithms (including Levenshtein edit distance and sibblings, Jaro-Winkler, Longest Common Subsequence, cosine similarity etc.) are currently implemented. The main characteristics of each implemented algorithm are presented below. The "cost" column gives an estimation of the computational cost to compute the similarity between two strings of length m and n respectively. If the alphabet is finite, it is possible to use the method of four russians (Arlazarov et al. "On economic construction of the transitive closure of a directed graph", 1970) to speedup computation. This was published by Masek in 1980 ("A Faster Algorithm Computing String Edit Distances").
    Downloads: 6 This Week
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  • 9
    SimMetrics is a Similarity Metric Library, e.g. from edit distance's (Levenshtein, Gotoh, Jaro etc) to other metrics, (e.g Soundex, Chapman). Work provided by UK Sheffield University funded by (AKT) an IRC sponsored by EPSRC, grant number GR/N15764/01.
    Downloads: 28 This Week
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  • 10
    This project has moved. Please follow the WWW link below.
    Downloads: 85 This Week
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  • 11
    X's Recommendation Algorithm

    X's Recommendation Algorithm

    Source code for the X Recommendation Algorithm

    The Algorithm is Twitter’s open source release of the core ranking system that powers the platform’s home timeline. It provides transparency into how tweets are selected, prioritized, and surfaced to users, reflecting Twitter’s move toward openness in recommendation algorithms. The repository contains the recommendation pipeline, which incorporates signals such as engagement, relevance, and content features, and demonstrates how they combine to form ranked outputs. Written primarily in Scala, it shows the architecture of large-scale recommendation systems, including candidate sourcing, ranking, and heuristics. While certain components (such as safety layers, spam detection, or private data) are excluded, the release provides valuable insights into the design of real-world machine learning–driven ranking systems. The project is intended as a reference for researchers, developers, and the public to study, experiment with, and better understand the mechanisms behind social media content.
    Downloads: 3 This Week
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  • 12
    leetcode-editor

    leetcode-editor

    Do Leetcode exercises in IDE

    Do Leetcode exercises in IDE, support leetcode.com and leetcode-cn.com, to meet the basic needs of doing exercises.Support theoretically: IntelliJ IDEA PhpStorm WebStorm PyCharm RubyMine AppCode CLion GoLand DataGrip Rider MPS Android Studio. The login accounts of the two websites are not interoperable and the corresponding users need to be configured when switching websites. You can also refresh and load questions if you are not logged in, but you cannot submit it. Input the content and press Enter to search , press again to search for the next one. It can only search under the question bank node. Clean up the files in the configured cache directories. The cache directories of the two websites are different and only the current configured websites are cleaned up. Carefully clean up cases without submitting.
    Downloads: 3 This Week
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  • 13
    The JTS Topology Suite is an API for modelling and manipulating 2-dimensional linear geometry. It provides numerous geometric predicates and functions. JTS conforms to the Simple Features Specification for SQL published by the Open GIS Consortium.
    Downloads: 13 This Week
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  • 14
    An open source workbench for chemo- and bioinformatics built on the Eclipse Rich Client Platform (RCP).
    Downloads: 27 This Week
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  • 15
    JGAP is a Genetic Algorithms and Genetic Programming package written in Java. It is designed to require minimum effort to use, but is also designed to be highly modular. JGAP features grid functionality and a lot of examples. Many unit tests included. Legal notice/Impressum: Klaus Meffert An der Struth 25 D-65510 Idstein sourceforge <at> klausmeffert.de
    Downloads: 19 This Week
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  • 16
    basE91 is an advanced method for encoding binary data as ASCII characters. It is similar to UUencode or base64, but is more efficient. The overhead produced by basE91 depends on the input data. It amounts at most to 23% and can range down to 14%.
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    Downloads: 75 This Week
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  • 17
    PLEASE NOTE that we are in the process of moving to GitHub: https://github.com/jasypt/jasypt Jasypt (Java Simplified Encryption) is a java library which allows the developer to add basic encryption capabilities to his/her projects with minimum effort, and without the need of having deep knowledge on how cryptography works. PLEASE NOTE that we are in the process of moving to GitHub: https://github.com/jasypt/jasypt
    Downloads: 14 This Week
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  • 18
    JCTools

    JCTools

    Java Concurrency Tools for the JVM

    Java Concurrency Tools for the JVM. This project aims to offer some concurrent data structures currently missing from the JDK. There’s more to come and contributions/suggestions are most welcome. JCTools has enjoyed support from the community and contributions in the form of issues/tests/documentation/code have helped it grow. JCTools offers excellent performance at a reasonable price (FREE! under the Apache 2.0 License). It’s stable and in use by such distinguished frameworks as Netty, RxJava and others. JCTools is also used by commercial products with great results. JCTools is maven built and requires an existing Maven installation and JDK8 (only for building, runtime is 1.6 compliant). With ‘MAVEN_HOME/bin’ on the path and JDK8 set to your ‘JAVA_HOME’ you should be able to run “mvn install” from this directory. While you are free to copy & extend JCTools, we would much prefer it if you have a versioned dependency on JCTools to enable better support, upgrade paths and discussion.
    Downloads: 2 This Week
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  • 19
    Groove
    NOTE: The GROOVE codebase has moved to https://github.com/nl-utwente-groove
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    Downloads: 15 This Week
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  • 20
    Taste
    Now part of Apache's Mahout machine learning project at http://mahout.apache.org/-- please see there for latest info and code and releases and support!
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    Downloads: 42 This Week
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  • 21

    Concurrency Freaks

    A library with Scalable (and fast) Read-Write locks

    This library contains Java code for several Read-Write Locks: - ScalableRWLock: A rw-lock that scales with the number of threads doing read-lock. - ScalableRWLockS: Similar to above but different implementation. - ScalableStampedRWLock: An hybrid of the ScalableRWLock and the StampedLock provided in JDK 8, which provides good overall performance. - FAARWLock: Uses a Fetch-And-Add operation for the read-lock which means it is not so scalable as ScalableRWLock but it is still faster than classical implementations
    Downloads: 35 This Week
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  • 22
    Structorizer
    Structorizer is a little tool which you can use to create Nassi-Schneiderman Diagrams (NSD). Stuctorizer is written in Java and free for any use. The code has been moved to Github: https://github.com/fesch/Structorizer.Desktop
    Downloads: 12 This Week
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  • 23
    SMSD

    SMSD

    SMSD is a Java based software library for calculating MCS.

    SMSD is a Java based software library for calculating Maximum Common Subgraph (MCS) between small molecules. This will help us to find similarity/distance between two molecules. MCS is also used for screening drug like compounds by hitting molecules, which share common subgraph (substructure).
    Downloads: 33 This Week
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  • 24
    Jenetics: Java Genetic Algorithm Library
    The source code has been migrated and is now hosted on Github: https://github.com/jenetics/jenetics Jenetics is an advanced Genetic Algorithm, Evolutionary Algorithm and Genetic Programming library, respectively, written in modern day Java. It is designed with a clear separation of the several algorithm concepts, e. g. Gene, Chromosome, Genotype, Phenotype, Population and fitness Function. Jenetics allows you to minimize or maximize the given fitness function without tweaking it. In contrast to other GA implementations, the library uses the concept of an evolution stream (EvolutionStream) for executing the evolution steps. Since the EvolutionStream implements the Java Stream interface, it works smoothly with the rest of the Java Stream API. Other repositories: - https://github.com/jenetics/jenetics Maven: - https://mvnrepository.com/artifact/io.jenetics
    Downloads: 6 This Week
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  • 25
    CloudI: A Cloud at the lowest level
    CloudI is an open-source private cloud computing framework for efficient, secure, and internal data processing. CloudI provides scaling for previously unscalable source code with efficient fault-tolerant execution of ATS, C/C++, Erlang/Elixir, Go, Haskell, Java, JavaScript/node.js, OCaml, Perl, PHP, Python, Ruby, or Rust services. The bare essentials for efficient fault-tolerant processing on a cloud!
    Downloads: 27 This Week
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