---
name: azure-communication-chat-java
description: "Build real-time chat applications with thread management, messaging, participants, and read receipts."
risk: critical
source: community
date_added: "2026-02-27"
---

# Azure Communication Chat (Java)

Build real-time chat applications with thread management, messaging, participants, and read receipts.

## Privacy and write scope

Examples are independent SDK fragments, not a complete tested application. Pin the package version and verify imports/API signatures against it before compiling. Use approved test participants and a least-privilege user token; sending messages, read receipts or typing events, changing history visibility and deleting threads require the corresponding user instruction. Minimize pagination and do not print production message bodies, tokens or participant identifiers into shared logs. Render received HTML only with an appropriate sanitizer; server acceptance does not make it safe UI markup.

## Installation

```xml
<dependency>
    <groupId>com.azure</groupId>
    <artifactId>azure-communication-chat</artifactId>
    <version>1.6.0</version>
</dependency>
```

## Client Creation

```java
import com.azure.communication.chat.ChatClient;
import com.azure.communication.chat.ChatClientBuilder;
import com.azure.communication.chat.ChatThreadClient;
import com.azure.communication.common.CommunicationTokenCredential;

// ChatClient requires a CommunicationTokenCredential (user access token)
String endpoint = "https://<resource>.communication.azure.com";
String userAccessToken = "<user-access-token>";

CommunicationTokenCredential credential = new CommunicationTokenCredential(userAccessToken);

ChatClient chatClient = new ChatClientBuilder()
    .endpoint(endpoint)
    .credential(credential)
    .buildClient();

// Async client
ChatAsyncClient chatAsyncClient = new ChatClientBuilder()
    .endpoint(endpoint)
    .credential(credential)
    .buildAsyncClient();
```

## Key Concepts

| Class | Purpose |
|-------|---------|
| `ChatClient` | Create/delete chat threads, get thread clients |
| `ChatThreadClient` | Operations within a thread (messages, participants, receipts) |
| `ChatParticipant` | User in a chat thread with display name |
| `ChatMessage` | Message content, type, sender info, timestamps |
| `ChatMessageReadReceipt` | Read receipt tracking per participant |

## Create Chat Thread

```java
import com.azure.communication.chat.models.*;
import com.azure.communication.common.CommunicationUserIdentifier;
import java.util.ArrayList;
import java.util.List;

// Define participants
List<ChatParticipant> participants = new ArrayList<>();

ChatParticipant participant1 = new ChatParticipant()
    .setCommunicationIdentifier(new CommunicationUserIdentifier("<user-id-1>"))
    .setDisplayName("Alice");

ChatParticipant participant2 = new ChatParticipant()
    .setCommunicationIdentifier(new CommunicationUserIdentifier("<user-id-2>"))
    .setDisplayName("Bob");

participants.add(participant1);
participants.add(participant2);

// Create thread
CreateChatThreadOptions options = new CreateChatThreadOptions("Project Discussion")
    .setParticipants(participants);

CreateChatThreadResult result = chatClient.createChatThread(options);
String threadId = result.getChatThread().getId();

// Get thread client for operations
ChatThreadClient threadClient = chatClient.getChatThreadClient(threadId);
```

## Send Messages

```java
// Send text message
SendChatMessageOptions messageOptions = new SendChatMessageOptions()
    .setContent("Hello, team!")
    .setSenderDisplayName("Alice")
    .setType(ChatMessageType.TEXT);

SendChatMessageResult sendResult = threadClient.sendMessage(messageOptions);
String messageId = sendResult.getId();

// Send HTML message
SendChatMessageOptions htmlOptions = new SendChatMessageOptions()
    .setContent("<strong>Important:</strong> Meeting at 3pm")
    .setType(ChatMessageType.HTML);

threadClient.sendMessage(htmlOptions);
```

## Get Messages

```java
import com.azure.core.util.paging.PagedIterable;

// List all messages
PagedIterable<ChatMessage> messages = threadClient.listMessages();

for (ChatMessage message : messages) {
    System.out.println("ID: " + message.getId());
    System.out.println("Type: " + message.getType());
    System.out.println("Content: " + message.getContent().getMessage());
    System.out.println("Sender: " + message.getSenderDisplayName());
    System.out.println("Created: " + message.getCreatedOn());
    
    // Check if edited or deleted
    if (message.getEditedOn() != null) {
        System.out.println("Edited: " + message.getEditedOn());
    }
    if (message.getDeletedOn() != null) {
        System.out.println("Deleted: " + message.getDeletedOn());
    }
}

// Get specific message
ChatMessage message = threadClient.getMessage(messageId);
```

## Update and Delete Messages

```java
// Update message
UpdateChatMessageOptions updateOptions = new UpdateChatMessageOptions()
    .setContent("Updated message content");

threadClient.updateMessage(messageId, updateOptions);

// Delete message
threadClient.deleteMessage(messageId);
```

## Manage Participants

```java
// List participants
PagedIterable<ChatParticipant> participants = threadClient.listParticipants();

for (ChatParticipant participant : participants) {
    CommunicationUserIdentifier user = 
        (CommunicationUserIdentifier) participant.getCommunicationIdentifier();
    System.out.println("User: " + user.getId());
    System.out.println("Display Name: " + participant.getDisplayName());
}

// Add participants
List<ChatParticipant> newParticipants = new ArrayList<>();
newParticipants.add(new ChatParticipant()
    .setCommunicationIdentifier(new CommunicationUserIdentifier("<new-user-id>"))
    .setDisplayName("Charlie")
    .setShareHistoryTime(OffsetDateTime.now().minusDays(7))); // Share last 7 days

threadClient.addParticipants(newParticipants);

// Remove participant
CommunicationUserIdentifier userToRemove = new CommunicationUserIdentifier("<user-id>");
threadClient.removeParticipant(userToRemove);
```

## Read Receipts

```java
// Send read receipt
threadClient.sendReadReceipt(messageId);

// Get read receipts
PagedIterable<ChatMessageReadReceipt> receipts = threadClient.listReadReceipts();

for (ChatMessageReadReceipt receipt : receipts) {
    System.out.println("Message ID: " + receipt.getChatMessageId());
    System.out.println("Read by: " + receipt.getSenderCommunicationIdentifier());
    System.out.println("Read at: " + receipt.getReadOn());
}
```

## Typing Notifications

```java
import com.azure.communication.chat.models.TypingNotificationOptions;

// Send typing notification
TypingNotificationOptions typingOptions = new TypingNotificationOptions()
    .setSenderDisplayName("Alice");

threadClient.sendTypingNotificationWithResponse(typingOptions, Context.NONE);

// Simple typing notification
threadClient.sendTypingNotification();
```

## Thread Operations

```java
// Get thread properties
ChatThreadProperties properties = threadClient.getProperties();
System.out.println("Topic: " + properties.getTopic());
System.out.println("Created: " + properties.getCreatedOn());

// Update topic
threadClient.updateTopic("New Project Discussion Topic");

// Delete thread
chatClient.deleteChatThread(threadId);
```

## List Threads

```java
// List all chat threads for the user
PagedIterable<ChatThreadItem> threads = chatClient.listChatThreads();

for (ChatThreadItem thread : threads) {
    System.out.println("Thread ID: " + thread.getId());
    System.out.println("Topic: " + thread.getTopic());
    System.out.println("Last message: " + thread.getLastMessageReceivedOn());
}
```

## Pagination

```java
import com.azure.core.http.rest.PagedResponse;

// Paginate through messages
int maxPageSize = 10;
ListChatMessagesOptions listOptions = new ListChatMessagesOptions()
    .setMaxPageSize(maxPageSize);

PagedIterable<ChatMessage> pagedMessages = threadClient.listMessages(listOptions);

pagedMessages.iterableByPage().forEach(page -> {
    System.out.println("Page status code: " + page.getStatusCode());
    page.getElements().forEach(msg -> 
        System.out.println("Message: " + msg.getContent().getMessage()));
});
```

## Error Handling

```java
import com.azure.core.exception.HttpResponseException;

try {
    threadClient.sendMessage(messageOptions);
} catch (HttpResponseException e) {
    switch (e.getResponse().getStatusCode()) {
        case 401:
            System.out.println("Unauthorized - check token");
            break;
        case 403:
            System.out.println("Forbidden - user not in thread");
            break;
        case 404:
            System.out.println("Thread not found");
            break;
        default:
            System.out.println("Error: " + e.getMessage());
    }
}
```

## Message Types

| Type | Description |
|------|-------------|
| `TEXT` | Regular chat message |
| `HTML` | HTML-formatted message |
| `TOPIC_UPDATED` | System message - topic changed |
| `PARTICIPANT_ADDED` | System message - participant joined |
| `PARTICIPANT_REMOVED` | System message - participant left |

## Environment Variables

```bash
AZURE_COMMUNICATION_ENDPOINT=https://<resource>.communication.azure.com
AZURE_COMMUNICATION_USER_TOKEN=<user-access-token>
```

## Best Practices

1. **Token Management** - User tokens expire; implement refresh logic with `CommunicationTokenRefreshOptions`
2. **Pagination** - Use `listMessages(options)` with `maxPageSize` for large threads
3. **Share History** - Set `shareHistoryTime` when adding participants to control message visibility
4. **Message Types** - Filter system messages (`PARTICIPANT_ADDED`, etc.) from user messages
5. **Read Receipts** - Send receipts only when messages are actually viewed by user

## Trigger Phrases

- "chat application Java", "real-time messaging Java"
- "chat thread", "chat participants", "chat messages"
- "read receipts", "typing notifications"
- "Azure Communication Services chat"

## When to Use
This skill is applicable to execute the workflow or actions described in the overview.

## Limitations
- Use this skill only when the task clearly matches the scope described above.
- Do not treat the output as a substitute for environment-specific validation, testing, or expert review.
- Stop and ask for clarification if required inputs, permissions, safety boundaries, or success criteria are missing.