> For the complete documentation index, see [llms.txt](https://rudderlabs.gitbook.io/rudderlabs-1/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://rudderlabs.gitbook.io/rudderlabs-1/docs/stream-sources/rudderstack-sdk-integration-guides/rudderstack-java-sdk.md).

# Java

Detailed technical documentation on using RudderStack’s Java SDK to send events to various destinations.

RudderStack’s Java SDK allows you to track your customer event data from your Java applications and send it to your specified destinations via RudderStack.

Check out the [**GitHub codebase**](https://github.com/rudderlabs/rudder-sdk-java) to get a more hands-on understanding of the SDK.

[![Github Badge](https://img.shields.io/maven-metadata/v.svg?label=Maven%20Central\&metadataUrl=https%3A%2F%2Frepo1.maven.org%2Fmaven2%2Fcom%2Frudderstack%2Fsdk%2Fjava%2Frudderanalytics-client%2Fmaven-metadata.xml)](https://search.maven.org/search?q=a:rudderanalytics-client)

## SDK setup requirements

To set up the RudderStack Java SDK, the following prerequisites must be met:

* You will need to set up a [**RudderStack account**](https://app.rudderstack.com).
* Once signed up, set up a Java source in the dashboard. For more information, follow [**this guide**](https://www.rudderstack.com/docs/rudderstack-cloud/sources/#adding-a-source). You should then see a **Write Key** for this source, as shown below:

![Java source write key](https://876606571-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F-Lq5Ea6fHVg3dSxMCgyQ%2Fuploads%2Fgit-blob-7bbecbec596df1f9f04dee2fb6137a07461d8569%2Fjava-sdk-1.png?alt=media)

* You will also need a data plane URL. Follow [**this section**](https://rudderstack.com/docs/rudderstack-open-source/installing-and-setting-up-rudderstack/#what-is-a-data-plane-url-where-do-i-get-it) for more information on the data plane URL and where to get it.

## Installing the Java SDK

**As Bintray has sunset from 1st may, 2021, we're moving our SDK to Maven Central. All the versions from 1.0.1 will now be available in Maven Central only.**

We distribute our Java SDK through [**Maven Central**](https://search.maven.org). The recommended and easiest way to add the SDK to your project is through the Maven build system.

To install the RudderStack Java SDK, add the following lines of code to `pom.xml`:

```markup
<dependency>
   <groupId>com.rudderstack.sdk.java.analytics</groupId>
     <artifactId>analytics</artifactId>
   <version>2.0.0</version>
</dependency>
```

If you're using Gradle, add the below to your dependencies:

```markup
implementation 'com.rudderstack.sdk.java.analytics:analytics:2.0.0'
```

## Initializing the RudderStack client

To initialize the RudderStack client, run the following code snippet:

```java
RudderAnalytics analytics = RudderAnalytics.builder(
        WRITE_KEY,
        DATA_PLANE_URL
).build();
```

## Sending events from the RudderStack client

Once the RudderStack client is initialized, you can use it to send relevant customer events from the RudderStack client.

RudderStack does not store the user state in any of the server-side SDKs. Unlike the client-side SDKs that deal with only a single user at a given time, the server-side SDKs deal with multiple users at the same time. Therefore, for any of the calls supported by the Java SDK, you need to specify either `userId` or `anonymousId` every time.

A sample `track` call is as shown:

```java
Map<String, Object> properties = new LinkedHashMap<>();
    properties.put("key1", "value1");
    properties.put("key2", "value2");
    analytics.enqueue(
       TrackMessage.builder("Java Test")
           .properties(properties)
           .anonymousId(anonymousId)
           .userId(userId)
);
```

## Identify

The `identify` call lets you identify a visiting user and capture any related information such as their name, email address, etc.

A sample `identify` call is as shown:

```java
analytics.enqueue(IdentifyMessage.builder()
    .userId("f4ca124298")
    .traits(ImmutableMap.builder()
        .put("name", "Sample Name")
        .put("email", "sample@abc.com")
        .build()
    )
);
```

The `identify` method parameters are as described below:

| **Field**      | **Type** | **Presence**                              | **Description**                                                                                                            |
| -------------- | -------- | ----------------------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
| `anonymousId`  | String   | Optional                                  | Sets the user ID for cases where there is no unique identifier for the user. Either `userId` or `anonymousId` is required. |
| `userId`       | String   | Optional, if `anonymousId` is already set | Unique identifier for a particular user in your database.                                                                  |
| `context`      | Object   | Optional                                  | Dictionary of information that provides context about a message. However, it is not directly related to the API call.      |
| `integrations` | Object   | Optional                                  | A dictionary containing the destinations to be either enabled or disabled.                                                 |
| `timestamp`    | Date     | Optional                                  | The timestamp of the message's arrival.                                                                                    |
| `traits`       | Object   | Optional                                  | Dictionary of the traits associated with the user, such as `name`or `email`                                                |

## Track

The `track` call lets you record the user actions along with their associated properties. Each user action is called an **event**.

A sample `track` call is shown below:

```java
Map<String, Object> properties = new LinkedHashMap<>();
    properties.put("key1", "value1");
    properties.put("key2", "value2");
    analytics.enqueue(
       TrackMessage.builder("Java Test")
           .properties(properties)
           .anonymousId(anonymousId)
           .userId(userId)
);
```

The `track` method parameters are as described below:

| Name           | Type   | Presence | Description                                                                                                                |
| -------------- | ------ | -------- | -------------------------------------------------------------------------------------------------------------------------- |
| `user_id`      | String | Required | The developer identification for your user                                                                                 |
| `event`        | String | Required | Name of the event being performed by the user                                                                              |
| `properties`   | Object | Optional | Dictionary of the properties associated with a particular event.                                                           |
| `context`      | Object | Optional | Dictionary of information that provides context about a message. However, it is not directly related to the API call.      |
| `timestamp`    | Date   | Optional | The timestamp of the message's arrival.                                                                                    |
| `anonymous_id` | String | Optional | Sets the user ID for cases where there is no unique identifier for the user. Either `userId` or `anonymousId` is required. |
| `integrations` | Object | Optional | A dictionary containing the destinations to be either enabled or disabled.                                                 |

## Page

The `page` call allows you to record the page views on your website along with the other relevant information about the viewed page.

A sample `page` call is as shown:

```java
analytics.enqueue(PageMessage.builder("Schedule")
    .userId("abcfgrg")
    .properties(ImmutableMap.builder()
        .put("category", "Cultural")
        .put("path", "/a/b")
        .build()
    )
);
```

The `page` method parameters are as described below:

| **Field**      | **Type** | **Presence**                              | **Description**                                                                                                            |
| -------------- | -------- | ----------------------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
| `anonymousId`  | String   | Optional                                  | Sets the user ID for cases where there is no unique identifier for the user. Either `userId` or `anonymousId` is required. |
| `userId`       | String   | Optional, if `anonymousId` is already set | Unique identifier for a particular user in your database.                                                                  |
| `context`      | Object   | Optional                                  | Dictionary of information that provides context about a message. However, it is not directly related to the API call.      |
| `integrations` | Object   | Optional                                  | A dictionary containing the destinations to be either enabled or disabled.                                                 |
| `name`         | String   | Required                                  | Name of the page being viewed.                                                                                             |
| `properties`   | Object   | Optional                                  | Dictionary of the properties associated with the page being viewed, such as `url` and `referrer`                           |
| `timestamp`    | Date     | Optional                                  | The timestamp of the message's arrival.                                                                                    |

## Screen

The `screen` call is the mobile equivalent of the `page` call. It allows you to record the screen views on your mobile app along with the other relevant information about the app screen.

A sample `screen` call is as shown:

```java
analytics.enqueue(ScreenMessage.builder("Schedule")
    .userId("f4ca124298")
    .properties(ImmutableMap.builder()
        .put("category", "Sports")
        .put("path", "/sports/schedule")
        .build()
    )
);
```

The `screen` method parameters are as described below:

| **Field**      | **Type** | **Presence**                              | **Description**                                                                                                            |
| -------------- | -------- | ----------------------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
| `anonymousId`  | String   | Optional                                  | Sets the user ID for cases where there is no unique identifier for the user. Either `userId` or `anonymousId` is required. |
| `userId`       | String   | Optional, if `anonymousId` is already set | Unique identifier for a particular user in your database.                                                                  |
| `context`      | Object   | Optional                                  | Dictionary of information that provides context about a message. However, it is not directly related to the API call.      |
| `integrations` | Object   | Optional                                  | A dictionary containing the destinations to be either enabled or disabled.                                                 |
| `name`         | String   | Required                                  | Name of the screen being viewed.                                                                                           |
| `properties`   | Object   | Optional                                  | Dictionary of the properties associated with the page being viewed, such as `url` and `referrer`                           |
| `timestamp`    | Date     | Optional                                  | The timestamp of the message's arrival.                                                                                    |

## Group

The `group` call lets you associate an identified user to a group - either a company, project or a team and record any custom traits or properties associated with that group.

A sample `group` call is as shown:

```python
analytics.enqueue(GroupMessage.builder("group123")
    .userId("f4ca124298")
    .traits(ImmutableMap.builder()
        .put("name", "Rudder")
        .put("size", 19)
        .build()
    )
);
```

The `group` method parameters are as follows:

| **Field**      | **Type** | **Presence**                              | **Description**                                                                                                            |
| -------------- | -------- | ----------------------------------------- | -------------------------------------------------------------------------------------------------------------------------- |
| `anonymousId`  | String   | Optional                                  | Sets the user ID for cases where there is no unique identifier for the user. Either `userId` or `anonymousId` is required. |
| `userId`       | String   | Optional, if `anonymousId` is already set | Unique identifier for a particular user in your database.                                                                  |
| `context`      | Object   | Optional                                  | Dictionary of information that provides context about a message. However, it is not directly related to the API call.      |
| `integrations` | Object   | Optional                                  | A dictionary containing the destinations to be either enabled or disabled.                                                 |
| `groupId`      | String   | Required                                  | Unique identifier of the group, as present in your database.                                                               |
| `traits`       | Object   | Optional                                  | Dictionary of the properties or traits associated with the group, such as `email` or `name`.                               |
| `timestamp`    | Date     | Optional                                  | The timestamp of the message's arrival.                                                                                    |

## Alias

The `alias` call allows you to associate one identity with another.

`alias` is an advanced method that lets you change the tracked user's ID explicitly. This method is useful when managing identities for some of the downstream destinations.

A sample `alias` call is as shown:

```java
analytics.enqueue(AliasMessage.builder("previousId")
    .userId("newId")
);
```

The `alias` method parameters are as mentioned below:

| **Field**      | **Type** | **Presence**                              | **Description**                                                                                                       |
| -------------- | -------- | ----------------------------------------- | --------------------------------------------------------------------------------------------------------------------- |
| `userId`       | String   | Optional, if `anonymousId` is already set | Unique identifier for a particular user in your database.                                                             |
| `context`      | Object   | Optional                                  | Dictionary of information that provides context about a message. However, it is not directly related to the API call. |
| `integrations` | Object   | Optional                                  | A dictionary containing the destinations to be either enabled or disabled.                                            |
| `previousId`   | String   | Required                                  | The previous unique identifier of the user.                                                                           |
| `traits`       | Object   | Optional                                  | Dictionary of the properties or traits associated with the group, such as `email` or `name`.                          |
| `timestamp`    | Date     | Optional                                  | The timestamp of the message's arrival.                                                                               |

For a detailed explanation of the `alias` call, refer to our [RudderStack API Specification](https://rudderstack.com/docs/rudderstack-api/api-specification/rudderstack-spec/alias/) guide.

## Block flush

This feature is only available from version `1.0.1` onwards.

If you want to block `flush` until all the events are uploaded , the Java SDK has a builder method called `synchronize()` with default value `false` which needs to be set to `true` .

An example for blocking the `flush` is shown:

```java
RudderAnalytics analytics = RudderAnalytics.builder(
        WRITE_KEY,
        DATA_PLANE_URL
)
// optional (default : false)
// Required to block further method invocation until the flush completes.
.synchronize(true);

// optional. Used for Logging
.plugin(new PluginLog());

// optional. Available from 2.0.0
//Sets the queue size at which flushes should be triggered.
.maximumQueueSizeInBytes(100); //maximum queue size

// optional. Available from 2.0.0
//Sets how many retries should happen before getting exhausted.
.retries(10); //number of retries

.build();

// ...YOUR CODE...

// optional. Triggers a flush and block until the flush completes.
// Required in case of Synchronize.
// It calls implicitly the `flush` method.
// So, explicit `flush` call is not required.
analytics.blockFlush();
analytics.shutdown(); // Shut down after the flush is complete.
```

## FAQs

### Can I use the `ImmutableMap` class?

Yes. You need to use the Guava library. You can also use the plain old Java Maps instead.

## Contact us

For queries on any of the sections covered in this guide, you can [**contact us**](mailto:%20docs@rudderstack.com) or start a conversation in our [**Slack**](https://rudderstack.com/join-rudderstack-slack-community) community.