nebula-java v1.x is composed of:

• Nebula Java v1.x, a Java client for developers to connect their projects to Nebula Graph.

  NOTE: Nebula Java is not thread-safe.

• Tools such as Nebula Graph Exchange, Nebula Spark Connector, Nebula Flink Connector, and nebula-algorithm. For more information, see nebula-java/tools.

This article gives a brief introduction to Nebula Java v1.x.

Nebula Java v1.x works with Nebula Graph v1.1.0 and earlier versions only.

If you are using Nebula Graph v2.0, go to the master branch. For more information, see README of v2.0.

Run this command to clone the source code:

git clone -b v1.0 https://github.com/vesoft-inc/nebula-java.git

To use Nebula Java v1.x, do a check of these:

• Java 8 or a later version is installed.
• Nebula Graph v1.1.0 or an earlier version is deployed.

If you use Maven to manage your project, add the following dependency to your pom.xml file. Replace 1.x.y with an appropriate Nebula Java v1.x version. For more versions, visit releases.

<dependency>
    <groupId>com.vesoft</groupId>
    <artifactId>client</artifactId>
    <version>1.x.y</version>
</dependency>

To connect to the nebula-graphd process:

GraphClient client = new GraphClientImpl("127.0.0.1", 3699);
client.setUser("user");
client.setPassword("password");
client.connect();

To use a graph space:

int code = client.switchSpace("space_test");

To execute a query:

int code = client.execute("CREATE TAG course(name string, credits int);");

When a query is executed successfully, 0 is returned. For a complete example, see Graph client example.

If you use the interface of RPC only, nothing need to be done.

If you want to directly use the storage client to encode and decode, you must use the JNI. You can get libnebula_codec.so from the nebula-utils jar package.

If the JNI cannot work in your environment, follow these steps to compile it:

1. Compile the dynamic link library.

2. Install the JNI jar into your local maven repository.

   mvn install:install-file -Dfile=${your-nebula-utils.jar} -DgroupId=com.vesoft -DartifactId=nebula-utils -Dversion={version} -Dpackaging=jar

See more Storage client examples about how to directly scan edges and vertices from the nebula-storaged process.

See Meta client example about how to get access to graph schemas.

Q: An error occurs during the process of building from the source code.

Failed to execute goal org.apache.maven.plugins:maven-gpg-plugin:1.6:sign (default) on project client: Exit code: 2 -> [Help 1]
org.apache.maven.lifecycle.LifecycleExecutionException: Failed to execute goal org.apache.maven.plugins:maven-gpg-plugin:1.6:sign (default) on project client: Exit code: 2

A: You must generate a key to sign the jars:

gpg --gen-key #generate your key pair
gpg --list-secret-keys #check if keys are generated successfully

Or you can skip gpg check when you compile the source code:

mvn clean compile package install -Dgpg.skip -Dmaven.javadoc.skip=true -Dtest.skip=true -Dmaven.test.skip=true