Slack SDK for Java supports all public Slack platform functionality in a Java idiomatic way. The SDK is completely written in Java, so that developers can use this SDK in any JVM language, including Kotlin, Groovy, and Scala without any hurdles.
The SDK offers two different modules depending on what platform features you intend to use:
- Slack API Client for calling a variety of Slack APIs
- Bolt for Java Framework for Slack App development with full platform features
If what you want to do is call Slack APIs in your existing services, we recommend using only the Slack API Client. If instead, you’re developing a new modern and interactive Slack app, we recommend Bolt for it. The framework enables developers to focus on the essential parts of their apps without being bothered by trifles.
slack-api-client contains simple, easy-to-use, and flexibly configurable HTTP clients for making requests to Slack APIs. Refer to API Client Basics for details.
import com.slack.api.Slack;
import com.slack.api.methods.response.chat.ChatPostMessageResponse;
Slack slack = Slack.getInstance();
String token = System.getenv("SLACK_TOKEN");
ChatPostMessageResponse response = slack.methods(token).chatPostMessage(req -> req
.channel("C1234567") // Channel ID
.text(":wave: Hi from a bot written in Java!"));Bolt for Java is a framework on the JVM that offers an abstraction layer to build Slack apps quickly using modern platform features. Refer to Getting Started with Bolt for detailed instructions.
package hello;
import com.slack.api.bolt.App;
import com.slack.api.bolt.jetty.SlackAppServer;
public class MyApp {
public static void main(String[] args) throws Exception {
// App expects env variables (SLACK_BOT_TOKEN, SLACK_SIGNING_SECRET)
App app = new App();
app.command("/hello", (req, ctx) -> {
return ctx.ack(":wave: Hello!");
});
SlackAppServer server = new SlackAppServer(app);
server.start(); // http://localhost:3000/slack/events
}
}The table below shows all the available modules. All of them have the same latest version as we release all at the same time, even in the case that some don't have any changes apart from updates on their dependency side.
All released versions are available on the Maven Central repositories. The latest version is
| groupId:artifactId | Description |
|---|---|
| com.slack.api:slack-api-model | This module is a collection of the classes representing the Slack core objects such as conversations, messages, users, surfaces, and blocks. As this one is an essential part of the SDK, all others depend on this. |
| com.slack.api:slack-api-client | This is a collection of the Slack API clients. The supported are Basic API Methods, RTM (Real Time Messaging) API, SCIM API, Audit Logs API, and Status API. |
| com.slack.api:slack-app-backend | This module is a set of Slack app server-side handlers and data classes for Events API, Interactive Components, Slash Commands, Actions, and OAuth flow. These are used by Bolt framework as the foundation of it in primitive layers. |
| com.slack.api:bolt | Bolt is a framework that offers an abstraction layer to build Slack apps safely and quickly. The most commonly used Servlet environment is supported out-of-the-box. |
| com.slack.api:bolt-servlet | This is an adapter for Servlet environments. |
| com.slack.api:bolt-jetty | This module offers a handy way to run Bolt apps on the Jetty HTTP server. |
| com.slack.api:bolt-aws-lambda | This module offers a handy way to run Bolt apps on AWS API Gateway + Lambda. |
| com.slack.api:bolt-micronaut | This is an adapter for Micronaut to run Bolt apps on top of it. |
| com.slack.api:bolt-helidon | This is an adapter for Helidon SE to run Bolt apps on top of it. |
The SDK supports OpenJDK 8 and higher LTS versions.
Users can expect every single patch release has been done after verifying functionality by running the basic CI builds with all LTS versions and all the unit tests have passed at least on the latest LTS version. We don't run comprehensive verifications with all OpenJDK distributions but it should be working with all of them.
If you get stuck, we’re here to help. The following are the best ways to get assistance working through your issue:
- Use our GitHub Issue Tracker for reporting bugs or requesting features
- Visit the Slack Developer Community for getting help using Slack SDK for Java or just generally bond with your fellow Slack developers.
The jSlack project has been transferred to @slackapi. The jSlack maintenance releases for security issues or major bugfixes will be continued at https://github.com/seratch/jslack-maintenance-releases .