Neo4j Bolt driver for Java

README.md

Neo4j Java Driver

This repository holds the official Java driver for Neo4j. The API is designed to work against both single instance and clustered databases.

For Driver Users

This section provides general information for developers who are building Neo4j-backed applications. Note that this driver is designed to be used only by Neo4j 3.0 and above and provides no HTTP capabilities.

Java Runtime

Recent drivers require the Java 8 or higher version of the runtime. The table below shows runtime compatibility for the currently-supported driver versions.

Driver Series Java 7 Java 8 Java 11
1.4 X X
1.5 X X
1.6 X X
1.7 X X

The automatic module name of the driver for the Java Module System is org.neo4j.driver.

The pom.xml file

The driver is distributed exclusively via Maven. To use the driver in your Maven project, include the following within your pom.xml file:

<dependency>
    <groupId>org.neo4j.driver</groupId>
    <artifactId>neo4j-java-driver</artifactId>
    <version>x.y.z</version>
</dependency>

Here, x.y.z will need to be replaced with the appropriate driver version. It is generally recommended to use the latest driver version wherever possible. This ensures access to new features and recent bug fixes. All available versions of this driver can be found at Maven Central or Releases.

Example

To run a simple query, the following can be used:

Driver driver = GraphDatabase.driver("bolt://localhost:7687", AuthTokens.basic("neo4j", "PasSW0rd"));
try (Session session = driver.session()) {
    StatementResult rs = session.run("CREATE (n) RETURN n");
}
driver.close();

For full applications, a single Driver object should be created with application-wide scope and lifetime. This allows full utilization of the driver connection pool. The connection pool reduces network overhead added by sharing TCP connections between subsequent transactions. Network connections are acquired on demand from the pool when running Cypher queries, and returned back to connection pool after query execution finishes. As a result of this design, it is expensive to create and close a Driver object. Session objects, on the other hand, are very cheap to use.

Thread Safety

Driver objects are thread-safe, but Session and Transaction objects should only be used by a single thread.

Further reading

Check out our Wiki for detailed and most up-to-date developer manuals, driver API documentations, changelogs, etc.

Bug Report

If you encounter any bugs while using this driver, please follow the instructions in our Contribution Guide when raising an issue at Issues.

When reporting, please mention the versions of the driver and server, as well as the server topology (single instance, causal cluster, etc). Also include any error stacktraces and a code snippet to reproduce the error if possible, as well as anything else that you think might be helpful.

For Driver Developers

This section targets users who would like to compile the driver source code on their own machine for the purpose of, for example, contributing a PR. Before contributing to this project, please take a few minutes to read our Contribution Guide.

Java Version

For the 1.5 series driver and above, source code must compile on Java 8. For previous versions, the compilation requires Java 7.

Building

The source code here reflects the current development status of a new driver version. To use the driver in a project, please use the released driver via Maven Central or check out the code with git tags of corresponding versions instead.

Running Tests and Creating a Package

The driver unit tests relies on latest boltkit installed on your local machine. If boltkit is not installed, then all tests that requires boltkit will be ignored and will not be executed.

The following Maven command shows how to run all tests and build the source code:

mvn clean install

When running integration tests, the driver would start a Neo4j instance and a Neo4j cluster on your local machine. Your tests might fail due to

  • a Neo4j server instance is already running on your machine and occupying the default server ports,
  • a lack of persmission to download Neo4j Enterprise artifacts.

To skip the integration tests, use:

mvn clean install -DskipITs

Windows

If you are building on windows, you will need to run the install with admin rights. This is because integration tests require admin privileges to install and start a service.