Azure Event Grid SDK for Java

Build event-driven applications using the Azure Event Grid SDK for Java.

Installation

<dependency> <groupId>com.azure</groupId> <artifactId>azure-messaging-eventgrid</artifactId> <version>4.27.0</version> </dependency>

Client Creation

EventGridPublisherClient

import com.azure.messaging.eventgrid.EventGridPublisherClient; import com.azure.messaging.eventgrid.EventGridPublisherClientBuilder; import com.azure.core.credential.AzureKeyCredential;

// With API Key EventGridPublisherClient<EventGridEvent> client = new EventGridPublisherClientBuilder() .endpoint("<topic-endpoint>") .credential(new AzureKeyCredential("<access-key>")) .buildEventGridEventPublisherClient();

// For CloudEvents EventGridPublisherClient<CloudEvent> cloudClient = new EventGridPublisherClientBuilder() .endpoint("<topic-endpoint>") .credential(new AzureKeyCredential("<access-key>")) .buildCloudEventPublisherClient();

With DefaultAzureCredential

import com.azure.identity.DefaultAzureCredentialBuilder;

EventGridPublisherClient<EventGridEvent> client = new EventGridPublisherClientBuilder() .endpoint("<topic-endpoint>") .credential(new DefaultAzureCredentialBuilder().build()) .buildEventGridEventPublisherClient();

Async Client

import com.azure.messaging.eventgrid.EventGridPublisherAsyncClient;

EventGridPublisherAsyncClient<EventGridEvent> asyncClient = new EventGridPublisherClientBuilder() .endpoint("<topic-endpoint>") .credential(new AzureKeyCredential("<access-key>")) .buildEventGridEventPublisherAsyncClient();

Event Types

Type Description

EventGridEvent

Azure Event Grid native schema

CloudEvent

CNCF CloudEvents 1.0 specification

BinaryData

Custom schema events

Core Patterns

Publish EventGridEvent

import com.azure.messaging.eventgrid.EventGridEvent; import com.azure.core.util.BinaryData;

EventGridEvent event = new EventGridEvent( "resource/path", // subject "MyApp.Events.OrderCreated", // eventType BinaryData.fromObject(new OrderData("order-123", 99.99)), // data "1.0" // dataVersion );

client.sendEvent(event);

Publish Multiple Events

List<EventGridEvent> events = Arrays.asList( new EventGridEvent("orders/1", "Order.Created", BinaryData.fromObject(order1), "1.0"), new EventGridEvent("orders/2", "Order.Created", BinaryData.fromObject(order2), "1.0") );

client.sendEvents(events);

Publish CloudEvent

import com.azure.core.models.CloudEvent; import com.azure.core.models.CloudEventDataFormat;

CloudEvent cloudEvent = new CloudEvent( "/myapp/orders", // source "order.created", // type BinaryData.fromObject(orderData), // data CloudEventDataFormat.JSON // dataFormat ); cloudEvent.setSubject("orders/12345"); cloudEvent.setId(UUID.randomUUID().toString());

cloudClient.sendEvent(cloudEvent);

Publish CloudEvents Batch

List<CloudEvent> cloudEvents = Arrays.asList( new CloudEvent("/app", "event.type1", BinaryData.fromString("data1"), CloudEventDataFormat.JSON), new CloudEvent("/app", "event.type2", BinaryData.fromString("data2"), CloudEventDataFormat.JSON) );

cloudClient.sendEvents(cloudEvents);

Async Publishing

asyncClient.sendEvent(event) .subscribe( unused -> System.out.println("Event sent successfully"), error -> System.err.println("Error: " + error.getMessage()) );

// With multiple events asyncClient.sendEvents(events) .doOnSuccess(unused -> System.out.println("All events sent")) .doOnError(error -> System.err.println("Failed: " + error)) .block(); // Block if needed

Custom Event Data Class

public class OrderData { private String orderId; private double amount; private String customerId;

public OrderData(String orderId, double amount) {
    this.orderId = orderId;
    this.amount = amount;
}

// Getters and setters

}

// Usage OrderData order = new OrderData("ORD-123", 150.00); EventGridEvent event = new EventGridEvent( "orders/" + order.getOrderId(), "MyApp.Order.Created", BinaryData.fromObject(order), "1.0" );

Receiving Events

Parse EventGridEvent

import com.azure.messaging.eventgrid.EventGridEvent;

// From JSON string (e.g., webhook payload) String jsonPayload = "[{"id": "...", ...}]"; List<EventGridEvent> events = EventGridEvent.fromString(jsonPayload);

for (EventGridEvent event : events) { System.out.println("Event Type: " + event.getEventType()); System.out.println("Subject: " + event.getSubject()); System.out.println("Event Time: " + event.getEventTime());

// Get data
BinaryData data = event.getData();
OrderData orderData = data.toObject(OrderData.class);

}

Parse CloudEvent

import com.azure.core.models.CloudEvent;

String cloudEventJson = "[{"specversion": "1.0", ...}]"; List<CloudEvent> cloudEvents = CloudEvent.fromString(cloudEventJson);

for (CloudEvent event : cloudEvents) { System.out.println("Type: " + event.getType()); System.out.println("Source: " + event.getSource()); System.out.println("ID: " + event.getId());

MyEventData data = event.getData().toObject(MyEventData.class);

}

Handle System Events

import com.azure.messaging.eventgrid.systemevents.*;

for (EventGridEvent event : events) { if (event.getEventType().equals("Microsoft.Storage.BlobCreated")) { StorageBlobCreatedEventData blobData = event.getData().toObject(StorageBlobCreatedEventData.class); System.out.println("Blob URL: " + blobData.getUrl()); } }

Event Grid Namespaces (MQTT/Pull)

Receive from Namespace Topic

import com.azure.messaging.eventgrid.namespaces.EventGridReceiverClient; import com.azure.messaging.eventgrid.namespaces.EventGridReceiverClientBuilder; import com.azure.messaging.eventgrid.namespaces.models.*;

EventGridReceiverClient receiverClient = new EventGridReceiverClientBuilder() .endpoint("<namespace-endpoint>") .credential(new AzureKeyCredential("<key>")) .topicName("my-topic") .subscriptionName("my-subscription") .buildClient();

// Receive events ReceiveResult result = receiverClient.receive(10, Duration.ofSeconds(30));

for (ReceiveDetails detail : result.getValue()) { CloudEvent event = detail.getEvent(); System.out.println("Event: " + event.getType());

// Acknowledge the event
receiverClient.acknowledge(Arrays.asList(detail.getBrokerProperties().getLockToken()));

}

Reject or Release Events

// Reject (don't retry) receiverClient.reject(Arrays.asList(lockToken));

// Release (retry later) receiverClient.release(Arrays.asList(lockToken));

// Release with delay receiverClient.release(Arrays.asList(lockToken), new ReleaseOptions().setDelay(ReleaseDelay.BY_60_SECONDS));

Error Handling

import com.azure.core.exception.HttpResponseException;

try { client.sendEvent(event); } catch (HttpResponseException e) { System.out.println("Status: " + e.getResponse().getStatusCode()); System.out.println("Error: " + e.getMessage()); }

Environment Variables

EVENT_GRID_TOPIC_ENDPOINT=https://<topic-name>.<region>.eventgrid.azure.net/api/events EVENT_GRID_ACCESS_KEY=<your-access-key>

Best Practices

• Batch Events: Send multiple events in one call when possible

• Idempotency: Include unique event IDs for deduplication

• Schema Validation: Use strongly-typed event data classes

• Retry Logic: Built-in, but consider dead-letter for failures

• Event Size: Keep events under 1MB (64KB for basic tier)

Trigger Phrases

• "Event Grid Java"

• "publish events Azure"

• "CloudEvent SDK"

• "event-driven messaging"

• "pub/sub Azure"

• "webhook events"