Top 23 Java High Performance Projects

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1. HikariCP

   1 37 20,505 8.8 Java

   光 HikariCP・A solid, high-performance, JDBC connection pool at last.

   

   Project mention: A Major Postgres Upgrade with Zero Downtime | news.ycombinator.com | 2025-01-29

   > are they using a connection pooler

   We use Hikari [1] an in-process connection pooler. We didn't opt for pgbouncer at al, because we didn't want to add the extra infra yet.

   > since what they did in code can be natively done with PgBouncer, PgCat, et al.

   Can you point me to a reference I could look at, about doing a major version upgrade with PgBouncer et al? My understanding that we would still need to write a script to switch masters, similar to what we wrote.

   > all the active connections

   The active connections we were referring too were websocket connections, we haven't had problems with PG connections.

   Right now the algorithm we use to find affected queries and notify websockets starts to falter when the number of active websocket connections get too high. We're working on improving it in the coming weeks. I'll update the essay to clarify.

   > I did feel for them here:

   Thank you! That part was definitely the most frustrating.

   [1] https://github.com/brettwooldridge/HikariCP

2. InfluxDB

   www.influxdata.com featured

   InfluxDB – Built for High-Performance Time Series Workloads. InfluxDB 3 OSS is now GA. Transform, enrich, and act on time series data directly in the database. Automate critical tasks and eliminate the need to move data externally. Download now.

   

3. Disruptor

   2 34 17,851 5.9 Java

   High Performance Inter-Thread Messaging Library

   

   Project mention: The LMAX Architecture (2011) | news.ycombinator.com | 2024-08-16

   LMAX have an open source version of the disruptor in GitHub https://github.com/LMAX-Exchange/disruptor

4. Vert.x

   3 50 14,504 9.6 Java

   Vert.x is a tool-kit for building reactive applications on the JVM

   

   Project mention: Ash Framework – Model your domain, derive the rest | news.ycombinator.com | 2025-05-14

5. seatunnel

   4 53 8,592 9.8 Java

   SeaTunnel is a next-generation super high-performance, distributed, massive data integration tool.

   

   Project mention: How to Build Real-Time Data Pipelines with SQL Server CDC and Apache SeaTunnel | dev.to | 2025-06-17

   Change Data Capture (CDC) is a powerful feature in SQL Server that enables real-time data integration by tracking INSERT, UPDATE, and DELETE operations on tables. In this article, we’ll explore how SQL Server CDC works, and how to integrate it seamlessly with Apache SeaTunnel to build efficient, scalable data pipelines for AI-ready systems.

6. fastjson2

   5 2 4,063 9.8 Java

   🚄 FASTJSON2 is a Java JSON library with excellent performance.

   

7. JCTools

   6 2 3,675 4.7 Java

   

8. Tablesaw

   7 5 3,646 7.7 Java

   Java dataframe and visualization library

   

   Project mention: Fahmatrix – A Lightweight, Pandas-Like DataFrame Library for Java (GitHub) | news.ycombinator.com | 2025-05-16

   Always great to see efforts to make working with data frames easier. Here are some similar data frame libraries for Java:

   https://github.com/jtablesaw/tablesaw

   https://github.com/dflib/dflib

   My preferred way is just use duckdb java API. I didn't see anything better in performance/efficiency. Also a SQL query is often easier to write

9. SaaSHub

   www.saashub.com featured

   SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

   

10. Agrona

    8 5 3,018 9.5 Java

    High Performance data structures and utility methods for Java

    

11. Eclipse Collections

    9 9 2,518 8.0 Java

    Eclipse Collections is a collections framework for Java with optimized data structures and a rich, functional and fluent API.

    

12. tlaplus

    10 40 2,451 9.4 Java

    TLC is a model checker for specifications written in TLA+. The TLA+Toolbox is an IDE for TLA+.

    

    Project mention: Do not die hard with TLA+ pt.1 | dev.to | 2025-02-15

    TLA+ toolbox binaries — a Java based TLA+ IDE;

13. fastutil

    11 4 1,890 5.2 Java

    fastutil extends the Java™ Collections Framework by providing type-specific maps, sets, lists and queues.

    

    Project mention: Do you know how to evaluate performance of your Java applications? | dev.to | 2025-02-27

    For a request with thousands of IDs (e.g., batch validation), each Integer requires unboxing. The alternative? Use int[] and IntHashSet (from the FastUtil library).

14. GS Collections

    12 2 1,817 0.0 Java

    GS Collections has been migrated to the Eclipse Foundation, re-branded as Eclipse Collections. https://www.eclipse.org/collections/

    

    Project mention: Common Java Libraries and Frameworks you Should Try | dev.to | 2024-10-15

    3. Eclipse Collections

15. bitsail

    13 1 1,652 6.6 Java

    BitSail is a distributed high-performance data integration engine which supports batch, streaming and incremental scenarios. BitSail is widely used to synchronize hundreds of trillions of data every day.

    

16. Rapidoid

    14 0 1,629 0.0 Java

    Rapidoid - Extremely Fast, Simple and Powerful Java Web Framework and HTTP Server!

    

17. Simple Java Mail

    15 2 1,254 7.5 Java

    Simple API, Complex Emails (Jakarta Mail smtp wrapper)

    

18. linstor-server

    16 1 1,084 9.3 Java

    High Performance Software-Defined Block Storage for container, cloud and virtualisation. Fully integrated with Docker, Kubernetes, Openstack, Proxmox etc.

    

19. DSL-JSON

    17 6 1,032 2.5 Java

    High performance JVM JSON library

    

20. Koloboke

    18 1 1,014 0.0 Java

    Java Collections till the last breadcrumb of memory and performance

    

    Project mention: Common Java Libraries and Frameworks you Should Try | dev.to | 2024-10-15

    9. Koloboke

21. HPPC

    19 0 1,014 8.0 Java

    High Performance Primitive Collections for Java

    

22. ActiveJ

    20 4 961 9.2 Java

    ActiveJ is an alternative Java platform built from the ground up. ActiveJ redefines core, web and high-load programming in Java, providing simplicity, maximum performance and scalability

    

23. cicada

    21 0 949 0.0 Java

    🚀 Fast lightweight HTTP service framework. (by TogetherOS)

    

24. Zero-Allocation-Hashing

    22 1 808 5.8 Java

    Zero-allocation hashing for Java

    

25. colfer

    23 1 749 4.4 Java

    binary serialization format

    

26. SaaSHub

    www.saashub.com featured

    SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives

    

Java High Performance related posts

• How to Build Real-Time Data Pipelines with SQL Server CDC and Apache SeaTunnel

  1 project | dev.to | 17 Jun 2025

• How to Seamlessly Integrate SeaTunnel MySQL-CDC with Databend: Formats Explained & Best Practices

  1 project | dev.to | 11 Jun 2025

• A New Paradigm of Natural Language Data Integration: In-depth Exploration of SeaTunnel MCP

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• Apache SeaTunnel has surpassed 8,500 GitHub Stars

  1 project | news.ycombinator.com | 20 May 2025

• Contributor Spotlight: How I Brought Apache SeaTunnel from First PR to Production

  1 project | dev.to | 14 May 2025

• Practical experience in deploying K8s clusters in Apache SeaTunnel separated cluster mode

  1 project | dev.to | 22 Apr 2025

• You’re Invited: Apache SeaTunnel Biweekly Community Meeting on April 8, 2025

  1 project | dev.to | 7 Apr 2025
• A note from our sponsor - SaaSHub
  www.saashub.com | 21 Jun 2025

  SaaSHub helps you find the best software and product alternatives Learn more →

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