# jankotek/mapdb

MapDB provides concurrent Maps, Sets and Queues backed by disk storage or off-heap-memory. It is a fast and easy to use embedded Java database engine.

Repository: https://github.com/jankotek/mapdb
Canonical: https://ross.abutalabs.com/products/mapdb
Homepage: https://mapdb.org
Language: Java
License: Apache-2.0
License Family: permissive
Last push: 2026-07-23T08:08:46+00:00

## Health v2 (maintenance only)
Score: 75/100 (v2, computed 2026-09-02T17:46:02.011165+00:00)
- activity 94, release rhythm 35, longevity 100
- inputs: {"age_days": 5129, "days_push": 41, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 5049, forks 877 (observed 2026-08-28T04:09:08.942878+00:00)

## What it is
MapDB is an embedded Java database engine that provides concurrent Maps, Sets, Lists and Queues backed by disk storage or off-heap memory. It combines the Java collections framework with database features like transactions, MVCC and incremental backups.

## Use cases
- store large Java collections on disk instead of heap
- replace an RDBMS with an embedded database in a Java app
- build a multilevel cache with expiration and disk overflow
- create off-heap collections not affected by garbage collection
- process and filter huge quantities of data locally
- persist a ConcurrentMap between application restarts

## When to choose
- you need an embedded, zero-administration database inside a JVM application
- your datasets exceed heap memory and you want off-heap or disk-backed collections
- you want a drop-in replacement for Java Maps, Sets or Queues with persistence
- you need transactions and MVCC without running a separate database server

## When to avoid
- you need a client-server database with multi-application access
- your project is polyglot and needs non-JVM clients
- you require SQL queries and rich relational features
- you need a distributed or replicated database across nodes

## Facets
- artifact type: library
- maturity: stable
- function: database, caching, serialization, concurrency
- domain: databases, developer-tools, performance
- platform: jvm, cross-platform
- tags: embedded-database, off-heap-memory, java-collections, disk-storage, mvcc

## Member repositories
- jankotek/mapdb (main) score 75

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:08.942878+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T18:17:21.894323+00:00, confidence not recorded.
  - readme: https://github.com/jankotek/mapdb (fetched 2026-08-28T04:09:08.942878+00:00, sha d2683d82b5d6)
  - homepage: https://mapdb.org (fetched 2026-08-29T08:57:48.392104+00:00, sha 07e028b19cb0)
- Data as of 2026-08-30T08:39:29.467469+00:00.