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Top 23 Java Database Projects
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Project mention: CLI to manage your SQL database schemas and migrations | news.ycombinator.com | 2025-11-01
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AppSignal
Monitoring that respects your time & budget. APM, error tracking, and dashboards for modern web apps. Ten-minute setup, transparent flat pricing, and support from engineers who actually use the product.
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Chat2DB
Chat2DB is a free, cross-platform, local-first database client and SQL workspace for developers, DBAs, analysts, and data teams. Connect to 40+ databases, manage data, edit and run SQL, and use your own AI model to generate, explain, and optimize queries. Available on desktop, web, Docker, and CLI, with MCP support.
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--- ## Step 4 — Choose the Right Pooler for Your Scale | Feature | PgBouncer | pgpool-II | Odyssey | |---|---|---|---| | Transaction mode | ✅ Excellent | ✅ Supported | ✅ Excellent | | Read replica routing | ❌ No | ✅ Built-in | ⚠️ Limited | | Protocol overhead | Very low | Moderate | Low | | Operational complexity | Low | High | Medium | Use PgBouncer for lightweight, high-performance pooling with minimal operational surface area. Use pgpool-II when you need read/write splitting and can absorb the configuration work. Odyssey from Yandex is worth evaluating at very high connection counts — its multi-threaded model handles scale that PgBouncer's single-threaded architecture cannot match above ~50k clients. --- ## Gotchas **`server_reset_query` in transaction mode.** In session mode, PgBouncer runs `DISCARD ALL` between clients. In transaction mode this is skipped — but a custom `server_reset_query` will still fire and break your session state assumptions. **`max_client_conn` lower than your thread count.** If your application has 200 threads but `max_client_conn = 100`, the remaining 100 threads block, timeout, and retry. That retry storm amplifies load exactly when you can least afford it. **No client-side `connect_timeout`.** Without it, blocked connections queue indefinitely. Set `connect_timeout=3000ms` at the pool level, not just at the Postgres level. --- ## Conclusion Most connection storms are self-inflicted through misconfiguration, not load. Audit your ORM's prepared statement behavior first, apply the pool size formula, then deploy PgBouncer with monitoring on `SHOW POOLS` and `SHOW STATS`. Pool saturation should trigger alerts before clients ever see errors. **Resources:** - [PgBouncer documentation](https://www.pgbouncer.org/config.html) - [HikariCP pool sizing analysis](https://github.com/brettwooldridge/HikariCP/wiki/About-Pool-Sizing) - [pgjdbc `preferQueryMode` reference](https://jdbc.postgresql.org/documentation/use/)
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shardingsphere
Empowering Data Intelligence with Distributed SQL for Sharding, Scalability, and Security Across All Databases.
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Project mention: Neo4j VS OrientDB - a user suggested alternative | libhunt.com/r/neo4j | 2026-08-31
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Project mention: How to Build Presto from Source - OSS Contribution Guide (Step by Step Tutorial) | dev.to | 2026-01-14
[Important Links] Presto Website: https://prestodb.io Join Slack: https://communityinviter.com/apps/prestodb/prestodb
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SaaSHub
SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives
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Project mention: Apache Doris 4.0: One Engine for Analytics, Full-Text Search, and Vector Search | dev.to | 2025-10-24
The latest version of Apache Doris is now available for download. Visit doris.apache.org for detailed release notes and upgrade guides, and join the Doris community to explore, test, and share your feedback.
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And this is, when it doesn't delete data randomly: https://github.com/trinodb/trino/issues/28885 (some enterprise open source was slop before AI even it seems)
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debezium
Change data capture for a variety of databases. Please log issues at https://github.com/debezium/dbz/issues.
Project mention: 7 Free Tools for Data Pipeline Reconciliation and Cross-Source Validation | dev.to | 2026-05-13Debezium is an open-source CDC (change data capture) platform that streams database changes - inserts, updates, deletes - from supported databases (PostgreSQL, MySQL, MongoDB, SQL Server) to downstream consumers via Apache Kafka.
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Project mention: Building Fault-Tolerant, Event-Driven Kafka Pipelines in Go: Reliable Reprocessing & Dead Letter Queues | dev.to | 2026-08-17
Since the introduction of KRaft, Kafka no longer requires Apache ZooKeeper® for managing cluster metadata. It uses Kafka itself instead. One advantage of the new KRaft mode is that you can have a single Kafka broker to handle both metadata and client requests in a small, local development environment. The docker-compose.yml file for this tutorial uses this approach, leading to faster startup times and simpler configuration. Note that, in a production setting, you'll have distinct Kafka brokers for handling requests and operating as a cluster controller.
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Project mention: War Story: We Survived a 2-Hour Outage with Redis 8.0 Cluster and Sentinel | dev.to | 2026-05-02
We recommend the official go-redis client for Go, redis-py for Python, and Jedis for Java, as all three have added support for Redis 8.0’s new Cluster and Sentinel features. Avoid using older clients or community-maintained forks that may not support Redis 8.0’s updated gossip protocol or slot migration logic. All three official clients include error handling for Sentinel failover events, which is critical for minimizing traffic drops during failover. We use go-redis v9.4.0 in production, which has handled 142k writes/sec with <0.01% error rate post-fix.
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starrocks
The world's fastest open query engine for sub-second analytics both on and off the data lakehouse. With the flexibility to support nearly any scenario, StarRocks provides best-in-class performance for multi-dimensional analytics, real-time analytics, and ad-hoc queries. A Linux Foundation project.
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Project mention: spawn alternatives - dbmate, Flyway, atlas, liquibase, and goose | libhunt.com/r/saward/spawn | 2026-09-07
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Apache Cassandra
Open source transactional distributed database. Linear scalability and proven fault-tolerance on commodity hardware or cloud infrastructure without compromising performance.
Apache Cassandra is a highly scalable, distributed NoSQL database built for write-heavy workloads, horizontal scaling, and tunable consistency, with no single point of failure. K8ssandra is an open-source operator that automates Cassandra provisioning, scaling, backups, and repairs on Kubernetes. This guide deploys a multi-node Cassandra cluster via the K8ssandra Operator, with cert-manager, persistent block storage, and a LoadBalancer service for external access.
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Android Debug Database
A library for debugging android databases and shared preferences - Make Debugging Great Again
I am Amit Shekhar, Founder @ Outcome School, I have taught and mentored many developers, and their efforts landed them high-paying tech jobs, helped many tech companies in solving their unique problems, and created many open-source libraries being used by top companies. I am passionate about sharing knowledge through open-source, blogs, and videos.
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Zeppelin
Web-based notebook that enables data-driven, interactive data analytics and collaborative documents with SQL, Scala and more.
Project mention: Woxi: Wolfram Mathematica Reimplementation in Rust | news.ycombinator.com | 2026-02-25I wonder if it would make a good Zeppelin interpreter. https://zeppelin.apache.org/
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SaaSHub
SaaSHub - Software Alternatives and Reviews. SaaSHub helps you find the best software and product alternatives
NOTE:
The open source projects on this list are ordered by number of github stars.
The number of mentions indicates repo mentiontions in the last 12 Months or
since we started tracking (Dec 2020).
Java Database discussion
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Neo4j VS OrientDB - a user suggested alternative
2 projects | 31 Aug 2026 -
CVE-2026-53561: Apache Hive HiveServer2 SAML Bearer Impersonation
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Arcadedb – Open-Source Multi-Model Graph Database
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Building Fault-Tolerant, Event-Driven Kafka Pipelines in Go: Reliable Reprocessing & Dead Letter Queues
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ScalarDB: Universal HTAP Engine
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A note from our sponsor - SaaSHub
www.saashub.com | 11 Oct 2026
Index
What are some of the best open-source Database projects in Java? This list will help you:
| # | Project | Stars |
|---|---|---|
| 1 | dbeaver | 52,003 |
| 2 | Chat2DB | 28,307 |
| 3 | HikariCP | 21,239 |
| 4 | shardingsphere | 20,804 |
| 5 | QuestDB | 17,429 |
| 6 | Neo4j | 17,293 |
| 7 | Presto | 16,754 |
| 8 | doris | 16,035 |
| 9 | Trino | 13,310 |
| 10 | debezium | 13,204 |
| 11 | Apache ZooKeeper | 12,816 |
| 12 | Jedis | 12,369 |
| 13 | starrocks | 12,165 |
| 14 | Realm | 11,459 |
| 15 | Flyway | 10,131 |
| 16 | Apache Cassandra | 10,118 |
| 17 | Android Debug Database | 8,691 |
| 18 | shardingsphere-elasticjob | 8,204 |
| 19 | hertzbeat | 7,416 |
| 20 | jOOQ | 6,793 |
| 21 | Leaf | 6,749 |
| 22 | Zeppelin | 6,663 |
| 23 | Hibernate | 6,469 |
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Monitoring that respects your time & budget
APM, error tracking, and dashboards for modern web apps. Ten-minute setup, transparent flat pricing, and support from engineers who actually use the product.
www.appsignal.com