Compiling and Running MapR-ES Java Apps

For producer and consumer applications that use the MapR-ES Java API, use Maven to compile and determine the application's dependencies. Then, when you run the application, specify those dependencies in the application's classpath.

Compile and Determine Dependencies

See MapR-ES Streams Sample Programs on GitHub for an example pom.xml file.

  1. Add MapR's Maven repository to your pom.xml file, if it is not already added:
    <repositories>
    <repository>
      <id>mapr-releases</id>
      <url>http://repository.mapr.com/nexus/content/repositories/releases</url>
      <snapshots><enabled>true</enabled></snapshots>
      <releases><enabled>true</enabled></releases>
    </repository>
</repositories>
  2. Add a dependency to the MapR Streams Java client (kakfa-clients) project:
    <dependency>
      <groupId>org.apache.kafka</groupId>
      <artifactId>kafka-clients</artifactId>
      <version><version selected from the repository></version>
</dependency>
    NOTE: The kafka-clients version mentioned above is an example. The actual version that your application requires is based on the current MEP and MapR version that you are running. The versions are listed in the following location: http://repository.mapr.com/nexus/content/groups/mapr-public/org/apache/kafka/kafka-clients/
  3. Add a dependency to the MapR Streams project:
    <dependency>
      <groupId>com.mapr.streams</groupId>
      <artifactId>mapr-streams</artifactId>
      <version><version selected from the repository></version>
</dependency>
    NOTE: The MapR Streams project version mentioned above is an example. The actual version that your application requires is based on the current MEP and MapR version that you are running. The versions are listed in the following location:http://repository.mapr.com/nexus/content/groups/mapr-public/com/mapr/streams/mapr-streams/
  4. Use Maven to compile the application and resolve dependencies. For example, you can run mvn clean package.

Run the Application

When you develop a Java application, you can use a dependency management tool such as Maven to compile your application. However, it is recommended that do the following instead:
  1. Compile the Java application without including dependencies
  2. Specify the required classpath when you submit the application to the cluster
If you choose to bundle the JAR file, and there is a mismatch between the bundled JAR file and the version that your MapR cluster expects, this can result in failures. The failures differ depending on the version of MapR you are using. For more information, see Using the MapR-FS JAR to Connect to the Cluster.

When the cluster is secure, the node must also have a mapr ticket configured for the user that runs the application.

You can use the following command to launch MapR-ES applications:
java -cp <classpath>:. -Djava.library.path=/opt/mapr/lib <main class JAR> <command line arguments>

References