Java

Dapr offers a variety of packages to help with the development of Java applications. Using them you can create Java clients, servers, and virtual actors with Dapr.

Prerequisites

• Dapr CLI installed
• Initialized Dapr environment
• JDK 17 or above:
  • Eclipse Temurin
  • Oracle JDK
  • OpenJDK
• Install one of the following build tools for Java:
  • Maven 3.x
  • Gradle 6.x

Import Dapr’s Java SDK

Next, import the Java SDK packages to get started. Select your preferred build tool to learn how to import.

• Maven
• Gradle

<project>
  ...
  <dependencies>
    ...
    <!-- Dapr's core SDK with all features, except Actors. -->
    <dependency>
      <groupId>io.dapr</groupId>
      <artifactId>dapr-sdk</artifactId>
      <version>1.19.0</version>
    </dependency>
    <!-- Dapr's SDK for Actors (optional). -->
    <dependency>
      <groupId>io.dapr</groupId>
      <artifactId>dapr-sdk-actors</artifactId>
      <version>1.19.0</version>
    </dependency>
    <!-- Dapr's SDK integration with SpringBoot (optional). -->
    <dependency>
      <groupId>io.dapr</groupId>
      <artifactId>dapr-sdk-springboot</artifactId>
      <version>1.19.0</version>
    </dependency>
    ...
  </dependencies>
  ...
</project>

dependencies {
...
    // Dapr's core SDK with all features, except Actors.
    compile('io.dapr:dapr-sdk:1.19.0')
    // Dapr's SDK for Actors (optional).
    compile('io.dapr:dapr-sdk-actors:1.19.0')
    // Dapr's SDK integration with SpringBoot (optional).
    compile('io.dapr:dapr-sdk-springboot:1.19.0')
}

Spring Boot compatibility

The Spring Boot integration modules (dapr-sdk-springboot and the dapr-spring-* modules) require Spring Boot 4.0 from SDK 1.19. To use Spring Boot 3.5, stay on SDK 1.18.x. Learn more in Spring Boot integration.

Netty version

The Dapr Java SDK uses gRPC with Netty. From SDK 1.19, the SDK pulls Netty 4.2.x transitively. A project that pins Netty 4.1.x directly, or that uses a dependency management file that manages Netty 4.1.x, can get a dependency conflict.

You can fix this by removing the Netty 4.1.x pin. You can also import the dapr-sdk-bom, which manages the Netty version that matches the gRPC version the SDK uses:

<dependencyManagement>
  <dependencies>
    <dependency>
      <groupId>io.dapr</groupId>
      <artifactId>dapr-sdk-bom</artifactId>
      <version>1.19.0</version>
      <type>pom</type>
      <scope>import</scope>
    </dependency>
  </dependencies>
</dependencyManagement>

For Spring Boot projects, import io.dapr.spring:dapr-spring-bom instead, which imports dapr-sdk-bom.

Try it out

Put the Dapr Java SDK to the test. Walk through the Java quickstarts and tutorials to see Dapr in action:

import io.dapr.client.DaprClient;
import io.dapr.client.DaprClientBuilder;

try (DaprClient client = (new DaprClientBuilder()).build()) {
  // sending a class with message; BINDING_OPERATION="create"
  client.invokeBinding(BINDING_NAME, BINDING_OPERATION, myClass).block();

  // sending a plain string
  client.invokeBinding(BINDING_NAME, BINDING_OPERATION, message).block();
}

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

Available packages