=== Guice

1) Add Guice dependency to your project:

[dependency, artifactId="jooby-guice"]
.

2) Install Guice:

.Installing Guice
[source, java, role = "primary"]
----

import io.jooby.di.GuiceModule;
import io.jooby.runApp;

public class App extends Jooby {

  {
    install(new GuiceModule());                     <1>
        
    get("/", ctx -> {
      MyService service = require(MyService.class); <2>
      return service.doSomething();
    });
}

  public static void main(String[] args) {
    runApp(args, App::new);
  }
}
----

.Kotlin
[source, kotlin, role = "secondary"]
----
import io.jooby.di.GuiceModule
import io.jooby.runApp

fun main(args: Array<String>) {
  runApp(args) {
    install(GuiceModule())                    <1>
    
    get ("/") {
      val service = require(MyService::class) <2>
      service.doSomething()
    }
  }
}
----

<1> Install Guice module
<2> The javadoc:Jooby[require, java.lang.Class] call is now resolved by Guice

==== Property Injection

Configuration properties can be injected using the `@Named` annotation:

.application.conf
[source, bash]
----
currency = USD
----

.Java
[source,java,role="primary"]
----

import javax.injext.Named;
import javax.injext.Inject;

public class BillingService {

  @Inject
  public BillingService(@Named("currency") String currency) {
    ...
  }

}
----

.Kotlin
[source,kotlin,role="secondary"]
----
class BillingService @Inject constructor(@Named("currency") currency: String) {
  ...
}
----

==== MVC routes

Guice will also provisioning MVC routes

.MVC and Guice
[source, java, role = "primary"]
----
import io.jooby.di.GuiceModule;
import io.jooby.runApp

public class App extends Jooby {

  {
    install(new GuiceModule());  <1>
          
    mvc(MyController.class);     <2>
  }

  public static void main(String[] args) {
    runApp(args, App::new);
  }
}
----

.Kotlin
[source, kotlin, role = "secondary"]
----
import io.jooby.di.GuiceModule
import io.jooby.runApp

fun main(args: Array<String>) {
  runApp(args) {
    install(GuiceModule())       <1>

    mvc(MyController::class)     <2>
  }
}
----

<1> Install Guice module
<2> Register a MVC route

The lifecycle of `MyController` is now managed by Guice. Also:

- In Guice, the default scope is `prototype` (creates a new instance per request)
- If you prefer a single instance add the `javax.inject.Singleton` annotation
