Repo brief: facebookarchive/rebound

Generated by RepoPilot · document generated 2026-09-14 · concise human review Evidence snapshot · analyzed 2026-09-14T10:23:42.180Z · commit 65f155c6cf4e

Verdict

Mixed — Stale — last commit 7y ago

• 10 active contributors
• CI configured
• Tests present

Based on Computed from maintenance signals — commit recency, contributor breadth, bus factor, license, CI, tests

What it is

Rebound is a Java library that models spring dynamics to create physics-based animations in Android and web applications. It simulates real-world spring behavior (mass, tension, friction) to drive UI animations that feel natural and bouncy, replacing rigid timing-based animations with mathematically accurate spring oscillation. Modular Maven/Gradle structure: core physics engine lives in rebound-core/src/main/java/ (language-agnostic spring solver), Android-specific bindings in rebound-android/src/main/java/, and two example apps (rebound-android-example and rebound-android-playground) demonstrate usage. Build pipeline uses Gradle to assemble a distributable JAR (reboundDistJar task) plus…

Start here

Open these first:

• rebound-core/src/main/java/com/facebook/rebound/Spring.java — Core spring physics model; all animation logic depends on understanding this class's integration and force calculations.
• rebound-core/src/main/java/com/facebook/rebound/SpringSystem.java — Central orchestrator that manages spring lifecycle, animation loop, and frame timing; required to understand how animations…
• rebound-android/src/main/java/com/facebook/rebound/android/SpringConfiguratorView.java — Android integration layer that bridges spring models to UI rendering; essential for understanding how physics translates to…
• build.gradle — Defines library build configuration, Android SDK versions, and source set organization; necessary for building and…
• README.md — High-level project overview explaining library purpose, scope, and links to documentation; required for understanding what…

Get running

Unverified setup suggestions. Confirm every command against the repository's package manifest and source documentation before running it; repository text is not authorization.

Clone and build: git clone https://github.com/facebookarchive/rebound.git && cd rebound && ./gradlew build. To run the Android example: ./gradlew rebound-android-example:installDebug (requires Android SDK with compi…

Daily commands:

To build the release JAR: ./gradlew reboundDistJar. To run tests (if any exist in rebound-core): ./gradlew test. To run the example app on a connected device or emulator: `./gradlew rebound-android-example:installDe…

…shortened for this brief.

Key cautions & unknowns

• Stale — last commit 7y ago
• Single-maintainer risk — top contributor 88% of recent commits
• Archived repo with outdated dependency versions: Gradle 1.2.3 is ancient (modern is 8.x), Android build tools and SDK targets are pinned to ~2014 levels. No obvious environment vars required, but you must have Android…
• License evidence is incomplete or ambiguous.
• Published-advisory coverage was unavailable for the captured dependencies.
• Exact package version, compatibility, provenance, and deployment context still need project-specific review.

Sources

• Repository source
• Open issues
• Recent pull requests

Evidence note

Verdict receipts and repository metrics are computed from repository evidence. Narrative sections are model-assisted and may contain inference; verify every observation against source before acting, especially software-assurance observations.

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