Java

• installed
• Initialized Dapr environment
• JDK 11 or above - the published jars are compatible with Java 8:
  • Oracle’s JDK 15
  • OpenJDK
• Install one of the following build tools for Java:
  • Gradle 6.x

dependencies {
...
    // Dapr's core SDK with all features, except Actors.
    compile('io.dapr:dapr-sdk:1.1.0'))
    // Dapr's SDK for Actors (optional).
    compile('io.dapr:dapr-sdk-actors:1.1.0')
    // Dapr's SDK integration with SpringBoot (optional).
    compile('io.dapr:dapr-sdk-springboot:1.1.0')
}

import io.dapr.client.DaprClient;
import io.dapr.client.DaprClientBuilder;
try (DaprClient client = (new DaprClientBuilder()).build()) {
  // invoke a 'GET' method (HTTP) skipping serialization: \say with a Mono<byte[]> return type
  // for gRPC set HttpExtension.NONE parameters below
  response = client.invokeMethod(SERVICE_TO_INVOKE, METHOD_TO_INVOKE, "{\"name\":\"World!\"}", HttpExtension.GET, byte[].class).block();
  // invoke a 'POST' method (HTTP) skipping serialization: to \say with a Mono<byte[]> return type     
  System.out.println(new String(response));
  // invoke a 'POST' method (HTTP) with serialization: \employees with a Mono<Employee> return type      
  Employee newEmployee = new Employee("Nigel", "Guitarist");
  Employee employeeResponse = client.invokeMethod(SERVICE_TO_INVOKE, "employees", newEmployee, HttpExtension.POST, Employee.class).block();
}

• For a full guide on service invocation visit .
• Visit Java SDK examples for code samples and instructions to try out service invocation

Save & get application state

• For a full list of state operations visit How-To: Get & save state.
• Visit for code samples and instructions to try out state management

Publish messages

import io.dapr.client.DaprClient;
import io.dapr.client.domain.Metadata;
import static java.util.Collections.singletonMap;
try (DaprClient client = (new DaprClientBuilder()).build()) {
  client.publishEvent(PUBSUB_NAME, TOPIC_NAME, message, singletonMap(Metadata.TTL_IN_SECONDS, MESSAGE_TTL_IN_SECONDS)).block();
}

Subscribe to messages

import com.fasterxml.jackson.databind.ObjectMapper;
import io.dapr.Topic;
import io.dapr.client.domain.CloudEvent;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RestController;
import reactor.core.publisher.Mono;
@RestController
public class SubscriberController {
  private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
  @Topic(name = "testingtopic", pubsubName = "${myAppProperty:messagebus}")
  @PostMapping(path = "/testingtopic")
  public Mono<Void> handleMessage(@RequestBody(required = false) CloudEvent cloudEvent) {
    return Mono.fromRunnable(() -> {
      try {
        System.out.println("Subscriber got: " + cloudEvent.getData());
        System.out.println("Subscriber got: " + OBJECT_MAPPER.writeValueAsString(cloudEvent));
      } catch (Exception e) {
    });
  }
}

• For a full list of state operations visit How-To: Publish & subscribe.
• Visit for code samples and instructions to try out pub/sub

Interact with output bindings

• For a full guide on output bindings visit .
• Visit Java SDK examples for code samples and instructions to try out output bindings

import com.fasterxml.jackson.databind.ObjectMapper;
import io.dapr.client.DaprClient;
import io.dapr.client.DaprClientBuilder;
import java.util.Map;
try (DaprClient client = (new DaprClientBuilder()).build()) {
  Map<String, String> secret = client.getSecret(SECRET_STORE_NAME, secretKey).block();
  System.out.println(JSON_SERIALIZER.writeValueAsString(secret));
}

• For a full guide on secrets visit .
• Visit Java SDK examples for code samples and instructions to try out retrieving secrets

Actors

import io.dapr.actors.ActorMethod;
import io.dapr.actors.ActorType;
import reactor.core.publisher.Mono;
@ActorType(name = "DemoActor")
public interface DemoActor {
  void registerReminder();
  @ActorMethod(name = "echo_message")
  String say(String something);
  void clock(String message);
  @ActorMethod(returns = Integer.class)
}

• For a full guide on actors visit How-To: Use virtual actors in Dapr.
• Visit for code samples and instructions to try actors

• Java SDK examples