Getting Started

This page walks you through setting up a Cassandra development environment from scratch.

Prerequisites

You need the following installed before building Cassandra:

Java Development Kit (JDK) — JDK 11 or 17 for building; JDK 17 or 21 for running Cassandra 6. Download from Eclipse Adoptium or your preferred vendor.
Apache Ant — Cassandra uses Ant as its build system. Install from ant.apache.org or via your package manager.
Git — git-scm.com
Python 3 — Required for running distributed tests (dtests) and cqlsh.

Verify your Java toolchain before you build:

java -version
javac -version

Clone the Repository

Fork the Apache Cassandra repository on GitHub, then clone your fork:

git clone https://github.com/<your-username>/cassandra.git
cd cassandra

Add the upstream remote so you can pull future changes:

git remote add upstream https://github.com/apache/cassandra.git

Initialize Submodules

Cassandra uses git submodules for dependencies such as Accord. Initialize them after cloning:

git submodule update --init --recursive

When starting a development branch for a JIRA ticket, use the helper script to create matching branches across submodules: .build/sh/development-switch.sh --jira CASSANDRA-<number> (Source: CONTRIBUTING.md)

Build Cassandra

Build the project with Ant:

ant

This compiles the source, downloads dependencies, and produces build artifacts. The first build usually takes about 5-10 minutes on a laptop; later builds are often 1-2 minutes.

Expected success output ends with something like:

BUILD SUCCESSFUL

To verify everything compiled correctly:

ant jar build-test

Expected success output:

BUILD SUCCESSFUL
Total time: ...

Run a Smoke Test

Run a single unit test to verify your build:

ant test -Dtest.name=org.apache.cassandra.utils.UUIDTest

For a single test class, a successful run typically ends with:

BUILD SUCCESSFUL
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0

Or run the full unit test suite:

ant test

The full unit suite takes much longer than a smoke test; use it when you are validating a wider change, not for every edit.

See Testing for comprehensive guidance on all test types.

Next Steps

Set up your IDE for IntelliJ IDEA or Eclipse
Read Contributing Code Changes for the contribution workflow
Review the Code Style guidelines

This page provides the essential getting-started workflow. For build helper scripts and Docker-based builds, see the .build/README.md in the Cassandra repository.