Open Source Java Algorithms

Technical analysis library with indicators like ADX, MACD, RSI, Stochastic, TRIX... includes also candlestick pattern recognition. Useful for trading application developpers using either Excel, .NET, Mono, Java, Perl or C/C++.

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.

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.

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

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.

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.

Free Java Flowchart simulator / interpreter

AhoCorasickDoubleArrayTrie is a Java implementation of the Aho–Corasick multi-pattern matching algorithm that is optimized using a Double-Array Trie data structure. It is designed for fast keyword scanning across large texts, where you want to search for many patterns simultaneously and efficiently. The core idea is to build an automaton from a dictionary of patterns, then stream through input text to emit matches with minimal overhead. By using a double-array trie representation, the project emphasizes performance and memory efficiency compared to simpler pointer-heavy trie structures, which can matter a lot for large dictionaries or latency-sensitive services. This makes it a strong fit for tasks like content filtering, entity/term spotting, dictionary-based annotation, or high-throughput log/text processing. In short, it’s a specialized, speed-focused library for industrial-strength multi-keyword matching in Java.

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.

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.

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.

NOTE: The GROOVE codebase has moved to https://github.com/nl-utwente-groove

An open source workbench for chemo- and bioinformatics built on the Eclipse Rich Client Platform (RCP).

jFuzzyLogic is a java implementation of a Fuzzy Logic software package. It implements a complete Fuzzy inference system (FIS) as well as Fuzzy Control Logic compliance (FCL) according to IEC 61131-7 (formerly 1131-7).

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%.

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

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.

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

Common Java data structure library used by multiple projects. See http://verdantium.blogspot.com/

DjVu++ is a user-friendly program that used to manipulate DjVu file formats such as eBooks with a penalty of editing features. The program introduce a free replacement for the property PDF format with similar resolution and smaller file size DjVu++ also support OCR to handle text in scanned books and images. The program shows good performance for English. In addition to the Arabic language to lead free and commercial software in this area. The main features of DjVu++ program are: o Manipulate DjVu files. o Support smaller size than PDF with the same performance. o DjVu++ supports two languages in the OCR technique (Arabic and English). o Read multiple documents at the same time with the new tabs feature. o DjVu++ supports multiple formats:  Convert PDF document into DjVu format with smaller file size and the same performance.  Convert DjVu into PDF format.  Combine images to a single DjVu document. Perform OCR operations on multiple image formats.

CADI is an implementation of the JPIP standard (JPEG2000 Interactive Protocol - Part 9). CADI includes a JPIP server, a JPIP proxy, and a JPIP Client. CADI is designed and programmed with the aim to provide a flexible framework to test and develop ne

Java Combinatorial Optimization Platform is used to solve combinatorial problems using common interface, providing means to easily add new algorithms and problems and to benchmark them.

TimeFinder automatically optimizes schedules (timetables) for universities and high schools. It makes manual timetabling for the timetabler easier via a Java GUI. Export+import is supported via xml and text formats. http://timefinder.sourceforge.net/

Processor Expert components and Eclipse examples and plugins.

PortugolViana é uma ferramenta open-source para edição/execução algorítmica. PortugolViana permite a edição de algoritmos em português (do Brasil e de Portugal) e a sua execução e monitorização.