Java Client

Ignite 3 clients connect to the cluster via a standard socket connection. Unlike Ignite 2.x, there are no separate Thin and Thick clients in Ignite 3. All clients are 'thin'.

Clients do not become a part of the cluster topology, never hold any data, and are not used as a destination for compute calculations.

Getting Started

Prerequisites

To use Java thin client, Java 11 or newer is required.

Installation

Java client can be added to your project by using maven:

<dependency>
    <groupId>org.apache.ignite</groupId>
    <artifactId>ignite-client</artifactId>
    <version>3.0.0</version>
</dependency>

Connecting to Cluster

To initialize a client, use the IgniteClient class, and provide it with the configuration:

Java

try (IgniteClient client = IgniteClient.builder()
  .addresses("127.0.0.1:10800")
  .build()
) {
  // Your code goes here
}

Authentication

To pass authentication information, use the IgniteClientAuthenticator class and pass it to IgniteClient builder:

Java

IgniteClientAuthenticator auth = BasicAuthenticator.builder().username("myUser").password("myPassword").build();
IgniteClient.builder()
    .addresses("127.0.0.1:10800")
    .authenticator(auth)
    .build();

Logging

To configure client logging, add loggerFactory:

IgniteClient client = IgniteClient.builder()
    .addresses("127.0.0.1")
    .loggerFactory(System::getLogger)  // Optional: this is the default
    .build();

The client logs connection errors, reconnects, and retries. By default, logging routes to java.util.logging (JUL) at INFO level.

For detailed configuration with Logback, Log4j2, or JUL, see Java Client Logging.

Client Metrics

Java

When running Java client, you need to enable metrics in the client builder:

IgniteClient client = IgniteClient.builder()
  .addresses("127.0.0.1:10800")
  .metricsEnabled(true)
  .build();

After that, client metrics will be available to any Java monitoring tool, for example JDK Mission Control.

Available Java Metrics

Metric name	Description
ConnectionsActive	The number of currently active connections.
ConnectionsEstablished	The number of established connections.
ConnectionsLost	The number of connections lost.
ConnectionsLostTimeout	The number of connections lost due to a timeout.
HandshakesFailed	The number of failed handshakes.
HandshakesFailedTimeout	The number of handshakes that failed due to a timeout.
RequestsActive	The number of currently active requests.
RequestsSent	The number of requests sent.
RequestsCompleted	The number of completed requests. Requests are completed once a response is received.
RequestsRetried	The number of request retries.
RequestsFailed	The number of failed requests.
BytesSent	The amount of bytes sent.
BytesReceived	The amount of bytes received.
StreamerBatchesSent	The number of data streamer batches sent.
StreamerItemsSent	The number of data streamer items sent.
StreamerBatchesActive	The number of in-flight data streamer batches.
StreamerItemsQueued	The number of queued data streamer items.

Client Connection Configuration

There is a number of configuration properties managing the connection between the client and Ignite cluster:

IgniteClient client = IgniteClient.builder()
  .addresses("127.0.0.1:10800")
  .connectTimeout(5000)
  .heartbeatInterval(30000)
  .heartbeatTimeout(5000)
  .operationTimeout(3000)
  .backgroundReconnectInterval(30000)
  .retryPolicy(new RetryLimitPolicy().retryLimit(8))
  .build();

Configuration name	Description
connectTimeout	Client connection timeout, in milliseconds.
heartbeatInterval	Heartbeat message interval, in milliseconds.
heartbeatTimeout	Heartbeat message timeout, in milliseconds.
operationTimeout	Operation timeout, in milliseconds.
backgroundReconnectInterval	Background reconnect interval, in milliseconds.
retryPolicy	Retry policy. By default, all read operations are retried up to 16 times, and write operations are not retried.