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# [Android Components](../../README.md) > Samples > Firefox Sync - Logins
A simple app showcasing the service-sync-logins component.
## Concepts
The main concepts shown in the sample app are:
* Usage of the asynchronous result type `SyncResult`.
* Login to Firefox Accounts that provides the necessary information to fetch the Logins from Firefox Sync.
* Getting the list of Logins from Firefox Sync.
## `SyncResult` usage
`SyncResult` represents a chainable asynchronous result, and is used as a convenient method of running potentially long-running tasks (eg. network requests, crypto operations) on threads outside of the UI thread.
A value or exception can be wrapped in an SyncResult:
```kotlin
val syncValue = SyncResult.fromValue(42)
val syncException = SyncResult.fromException(Exception("Something went wrong"))
```
One can attach `OnValueListener`s or `OnExceptionListener`s to an `SyncResult`. There are a few ways of chaining results in Kotlin:
* Passing the listeners directly via `then`, with object expressions or otherwise:
```kotlin
SyncResult.fromValue(42).then(object : OnValueListener<Integer, Void> {
override fun onValue(value: Integer): SyncResult<Void>? {
// handle the value
return SyncResult<Void>()
}
}, object : OnExceptionListener<Void> {
override fun onException(exception: Exception): SyncResult<Void>? {
// handle the exception
return SyncResult<Void>()
}
})
```
Since Java 6 does not support simple lambda syntax, this is one of the main ways to chain `SyncResult`s in Java.
* Passing lambdas via `then`:
```kotlin
SyncResult.fromValue(42).then({ value: Int -> // valueListener
// handle the value
return SyncResult<Void>()
}, { exception: Exception ->
// handle the exception
return SyncResult<Void>()
})
```
* Completing a chain via `whenComplete`:
```kotlin
SyncResult.fromValue(42).whenComplete { value: Integer ->
// handle the value
}
```
Since `whenComplete` implies that the chain of promises has come to an end, there is no need to return another SyncResult at the end.
## License
This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this