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MongoDB Realm Java SDK

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  • Local Realm Database
  • Define an Object Schema
  • Query Realm Database
  • Update Live Objects
  • Watch for Object Updates
  • Always Access the Latest Data
  • Realm Apps
  • Realm Sync
  • App Services
  • Get Started
  • Advanced Guides

The MongoDB Realm Java SDK allows you to use Realm Database and backend Realm apps using Java or Kotlin.

MongoDB Realm's Java SDK enables you to build apps for the following platforms:

  • Android
  • Wear OS
  • Android Automotive OS
  • Android TV
  • Android Things

With the MongoDB Realm Java SDK, you can access objects stored in a local instance of Realm Database. With Realm Database, you can:

Define your object schema with annotated Kotlin or Java classes:

Query for stored objects using Android-native queries:

Update objects in Realm Database by updating field values on an instance of the object within a transaction:

Receive object updates and notifications automatically when objects stored in Realm Database change:

Live objects keep all instances of an object up to date at all times:

See also:

To get started with Realm Database, try our Local-only Quick Start.

Realm apps are backends for client applications hosted by MongoDB in the cloud. They provide the ability to synchronize data stored in Realm Database, called Realm Sync, as well as a layer of backend functionality collectively called App Services. The MongoDB Realm Java SDK optionally contains the ability to access these Realm apps running in the cloud. In addition to local Realm Database in the SDK, Realm apps provide the following functionality:

Automatically sync data between realms on client devices and your backend MongoDB Atlas data store with Realm Sync:

See also:

To get started with MongoDB Realm, try the our Quick Start with Sync.

To start using the MongoDB Realm Java SDK in your Android application, see the installation guide to add the SDK dependency. Then check out the Quick Start.

To learn more about the concepts that underlie Realm Database, such as the Asynchronous API, the Query Engine, and more, check out the Fundamentals.

For practical code samples of common tasks in Realm Database and Realm apps, take a look at the Examples.

Get Started
Realm Apps Examples
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