Apache DataFusion Java

Java bindings for Apache DataFusion. Queries run in native Rust and results return to the JVM as Apache Arrow batches via the Arrow C Data Interface.

Early development: the API will change between releases. Bug reports and contributions welcome.

Install

Released to Maven Central. The JAR bundles the native library for Linux and macOS on x86_64 and aarch64. Windows users need to build from source.

Maven:

<dependency>
    <groupId>org.apache.datafusion</groupId>
    <artifactId>datafusion-java</artifactId>
    <version>0.1.0</version>
</dependency>

Gradle:

implementation("org.apache.datafusion:datafusion-java:0.1.0")

Arrow needs --add-opens=java.base/java.nio=ALL-UNNAMED on the JVM command line. See the installation guide for details and for building from source.

Quickstart

import org.apache.arrow.memory.RootAllocator;
import org.apache.arrow.vector.ipc.ArrowReader;
import org.apache.datafusion.DataFrame;
import org.apache.datafusion.SessionContext;

try (var allocator = new RootAllocator();
     var ctx = new SessionContext()) {

    ctx.registerParquet("orders", "/path/to/orders.parquet");

    try (DataFrame df = ctx.sql(
            "SELECT o_orderpriority, COUNT(*) AS n " +
            "FROM orders GROUP BY o_orderpriority");
         ArrowReader reader = df.collect(allocator)) {
        while (reader.loadNextBatch()) {
            var batch = reader.getVectorSchemaRoot();
            // ...
        }
    }
}

SessionContext and DataFrame are AutoCloseable and not thread-safe.

Documentation

The full documentation lives under docs/source/ and is built with Sphinx (see docs/README.md for the build steps):

  • User guide — installation, the DataFrame and SQL APIs, Parquet ingestion.
  • Contributor guide — build, test, code style, and how to bump the DataFusion version.

Requirements

JDK 17+. Building from source: see docs/source/contributor-guide/development.md.

Contributing

Open an issue to discuss non-trivial changes before sending a PR. See the contributor guide.

License

Apache License 2.0. See LICENSE.txt and NOTICE.txt.