Java quick start

At the end of this guide, you will have created a simple Java console Hello, World! program that connects to the Memgraph database and executes simple queries.

Prerequisites

For this guide you will need:

• A running Memgraph instance. If you need to set up Memgraph, take a look at the Installation guide.
• A basic understanding of graph databases and the property graph model.
• Java 8 or 11 installed.

Basic Setup

We'll be using Eclipse IDE 2020-09 on Windows 10 to connect a simple Java console application to a running Memgraph instance using Maven. If you're using a different IDE, the steps might be slightly different, but the code is probably the same or very similar.

Let's jump in and connect a simple program to Memgraph.

1. Open Eclipse and create a new Maven project.

2. Select the Create a simple project option.

3. For the Group Id field put com.memgraph.app and for Artifact Id put my-app. Afterwards, click the Finish button.

4. Open the pom.xml file and add the following dependency:

<dependencies>
    <dependency>
      <groupId>org.neo4j.driver</groupId>
      <artifactId>neo4j-java-driver</artifactId>
      <version>4.1.1</version>
    </dependency>
  </dependencies>

5. Create the HelloWorld.java program and copy the following code:

import org.neo4j.driver.AuthTokens;
import org.neo4j.driver.Driver;
import org.neo4j.driver.GraphDatabase;
import org.neo4j.driver.Session;
import org.neo4j.driver.Result;
import org.neo4j.driver.Transaction;
import org.neo4j.driver.TransactionWork;

import static org.neo4j.driver.Values.parameters;

public class HelloWorld implements AutoCloseable
{
    private final Driver driver;

    public HelloWorld( String uri, String user, String password )
    {
        driver = GraphDatabase.driver( uri, AuthTokens.basic( user, password ) );
    }

    public void close() throws Exception
    {
        driver.close();
    }

    public void printGreeting( final String message )
    {
        try ( Session session = driver.session() )
        {
            String greeting = session.writeTransaction( new TransactionWork<String>()
            {
                @Override
                public String execute( Transaction tx )
                {
                    Result result = tx.run( "CREATE (a:Greeting) " +
                                                     "SET a.message = $message " +
                                                     "RETURN 'Node ' + id(a) + ': ' + a.message",
                            parameters( "message", message ) );
                    return result.single().get( 0 ).asString();
                }
            } );
            System.out.println( greeting );
        }
    }

    public static void main( String... args ) throws Exception
    {
        try ( HelloWorld greeter = new HelloWorld( "bolt://localhost:7687", "", "" ) )
        {
            greeter.printGreeting( "Hello, World!" );
        }
    }
}

Once you run the program, you should see an output similar to the following:

Node 1: Hello, World!

Where to next?

For real-world examples of how to use Memgraph, we suggest you take a look at the Tutorials page. You can also browse through the Database functionalities section to get an overview of all the functionalities Memgraph offers.

Getting help

Visit the Getting help page in case you run into any kind of problem or you have additional questions.