> ## Documentation Index
> Fetch the complete documentation index at: https://cometchat-22654f5b-docs-audit-content-webhooks.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Join A Group

## Join a Group

In order to start participating in group conversations, you will have to join a group. You can do so using the `joinGroup()` method.

<Tabs>
  <Tab title="Java">
    ```java theme={null}
    private String GUID = "GUID";
    private String groupType = CometChatConstants.GROUP_TYPE_PUBLIC;
    private String password = "";

    CometChat.joinGroup(GUID, groupType, password, new CometChat.CallbackListener<Group>() {
      @Override
      public void onSuccess(Group joinedGroup) {
        Log.d(TAG, joinedGroup.toString());
      }
      @Override
      public void onError(CometChatException e) {
        Log.d(TAG, "Group joining failed with exception: " + e.getMessage());
      }
    });
    ```
  </Tab>

  <Tab title="Kotlin">
    ```kotlin theme={null}
    val GUID:String="GUID"
    val groupType:String=CometChatConstants.GROUP_TYPE_PUBLIC
    val password:String=""


    CometChat.joinGroup(GUID,groupType,password,object:CometChat.CallbackListener<Group>(){
      override fun onSuccess(p0: Group?) {
        Log.d(TAG, p0.toString());
      }
      override fun onError(p0: CometChatException?) {
        Log.d(TAG, "Group joining failed with exception: " + p0?.message)
      }
    })
    ```
  </Tab>
</Tabs>

The `joinGroup()` method takes the below parameters

| Parameter   | Description                                                                                                                                                                                                              |
| ----------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `GUID`      | The GUID of the group you would like to join                                                                                                                                                                             |
| `groupType` | Type of the group. CometChat provides 3 types of groups viz. 1.CometChatConstants.GROUP\_TYPE\_PUBLIC (public) 2.CometChatConstants.GROUP\_TYPE\_PASSWORD (password) 3.CometChatConstants.GROUP\_TYPE\_PRIVATE (private) |
| `password`  | Password is mandatory in case of a password protected group.                                                                                                                                                             |

Once you have joined a group successfully, you can send and receive messages in that group.

CometChat keeps a track of the groups joined and you do not need to join the group everytime you want to communicate in the group.

You can identify if a group is joined using the `hasJoined` parameter in the `Group` object.

## Real-time Group Member Joined Events

*In other words, as a member of a group, how do I know if someone joins the group when my app is running?*

If a user joins any group, the members of the group receive a real-time event in the `onGroupMemberJoined()` method of the `GroupListener` class.

<Tabs>
  <Tab title="Java">
    ```java theme={null}
    CometChat.addGroupListener(UNIQUE_LISTENER_ID, new CometChat.GroupListener() {
      @Override
      public void onGroupMemberJoined(Action action, User joinedUser, Group joinedGroup) {
        Log.d(TAG, "User joined");
      }
    });
    ```
  </Tab>

  <Tab title="Kotlin">
    ```kotlin theme={null}
    CometChat.addGroupListener(UNIQUE_LISTENER_ID, object : GroupListener() {
      override fun onGroupMemberJoined(action: Action?, joinedUser: User?, joinedGroup: Group?) {
        Log.d(TAG, "User joined")
      }
    })
    ```
  </Tab>
</Tabs>

## Missed Group Member Joined Events

*In other words, as a member of a group, how do I know if someone joins the group when my app is not running?*

When you retrieve the list of previous messages if a member has joined any group that the logged-in user is a member of, the list of messages will contain an `Action` message. An `Action` message is a sub-class of `BaseMessage` class.

For the group member joined event, in the `Action` object received, the following fields can help you get the relevant information-

1. `action` - `joined`
2. `actionBy` - User object containing the details of the user who joined the group
3. `actionFor`- Group object containing the details of the group the user has joined