Error when trying to use Elasticsearch Transport Client: dependencies not loaded to class path

Question

I am using the following code to create a client on Elasticsearch:

Settings settings = Settings.builder()
    .put("cluster.name", "myClusterName")
    .build();
TransportClient client = new PreBuiltTransportClient(settings)
    .addTransportAddress(newInetSocketTransportAddress(InetAddress.getByName("127.0.0.1"), 9300));

I am getting these errors:

Exception in thread "main" java.lang.NoClassDefFoundError: org/elasticsearch/plugins/ActionPlugin
    at java.lang.ClassLoader.defineClass1(Native Method)
    at java.lang.ClassLoader.defineClass(ClassLoader.java:763)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.URLClassLoader.defineClass(URLClassLoader.java:467)
    at java.net.URLClassLoader.access$100(URLClassLoader.java:73)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:368)
    at java.net.URLClassLoader$1.run(URLClassLoader.java:362)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(URLClassLoader.java:361)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    at org.elasticsearch.transport.client.PreBuiltTransportClient.<clinit>(PreBuiltTransportClient.java:54)
    at exadatum.com.exadatum.elastic.testSearch.main(testSearch.java:30)
Caused by: java.lang.ClassNotFoundException: org.elasticsearch.plugins.ActionPlugin
    at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:331)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
    ... 14 more

Answer 1

Update: this is now documented at

• https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/_log4j_2_logger.html
• https://www.elastic.co/guide/en/elasticsearch/client/java-api/current/_using_another_logger.html

---

Make sure the client dependency has been added to the class path:

<dependency>
    <groupId>org.elasticsearch.client</groupId>
    <artifactId>transport</artifactId>
    <version>5.0.0-rc1</version>
</dependency>

This dependency may not be loading transitively from child dependencies.

---

You may also find that the main Elasticsearch and Apache Logging artifacts need to be on the class path as well:

<dependency>
    <groupId>org.elasticsearch</groupId>
    <artifactId>elasticsearch</artifactId>
    <version>5.0.0-rc1</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-api</artifactId>
    <version>2.7</version>
</dependency>
<dependency>
    <groupId>org.apache.logging.log4j</groupId>
    <artifactId>log4j-core</artifactId>
    <version>2.7</version>
</dependency>