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Application Initialization and Termination

You often need to execute custom actions when the application starts and clean up everything when the application stops. This guide explains how to:

Write a Quarkus application with a main method
Write command mode applications that run a task and then terminate
Be notified when the application starts
Be notified when the application stops

Prerequisites

To complete this guide, you need:

Roughly 15 minutes
An IDE
JDK 17+ installed with JAVA_HOME configured appropriately
Apache Maven 3.9.9
Optionally the Quarkus CLI if you want to use it
Optionally Mandrel or GraalVM installed and configured appropriately if you want to build a native executable (or Docker if you use a native container build)

Solution

We recommend that you follow the instructions in the next sections and create the application step by step. However, you can go right to the completed example.

Clone the Git repository: git clone https://github.com/quarkusio/quarkus-quickstarts.git, or download an archive.

The solution is located in the lifecycle-quickstart directory.

Creating the Maven project

First, we need a new project. Create a new project with the following command:

CLI

quarkus create app org.acme:lifecycle-quickstart \
    --no-code
cd lifecycle-quickstart

To create a Gradle project, add the --gradle or --gradle-kotlin-dsl option.

For more information about how to install and use the Quarkus CLI, see the Quarkus CLI guide.

Maven

mvn io.quarkus.platform:quarkus-maven-plugin:3.16.4:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=lifecycle-quickstart \
    -DnoCode
cd lifecycle-quickstart

To create a Gradle project, add the -DbuildTool=gradle or -DbuildTool=gradle-kotlin-dsl option.

For Windows users:

If using cmd, (don’t use backward slash \ and put everything on the same line)
If using Powershell, wrap -D parameters in double quotes e.g. "-DprojectArtifactId=lifecycle-quickstart"

It generates:

the Maven structure
example Dockerfile files for both native and jvm modes
the application configuration file

The main method

By default, Quarkus will automatically generate a main method, that will bootstrap Quarkus and then just wait for shutdown to be initiated. Let’s provide our own main method:

package com.acme;

import io.quarkus.runtime.annotations.QuarkusMain;
import io.quarkus.runtime.Quarkus;

@QuarkusMain  (1)
public class Main {

    public static void main(String ... args) {
        System.out.println("Running main method");
        Quarkus.run(args); (2)
    }
}

1	This annotation tells Quarkus to use this as the main method, unless it is overridden in the config
2	This launches Quarkus

This main class will bootstrap Quarkus and run it until it stops. This is no different to the automatically generated main class, but has the advantage that you can just launch it directly from the IDE without needing to run a Maven or Gradle command.

It is not recommenced to do any business logic in this main method, as Quarkus has not been set up yet, and Quarkus may run in a different ClassLoader. If you want to perform logic on startup use an io.quarkus.runtime.QuarkusApplication as described below.

If we want to actually perform business logic on startup (or write applications that complete a task and then exit) we need to supply a io.quarkus.runtime.QuarkusApplication class to the run method. After Quarkus has been started the run method of the application will be invoked. When this method returns the Quarkus application will exit.

If you want to perform logic on startup you should call Quarkus.waitForExit(), this method will wait until a shutdown is requested (either from an external signal like when you press Ctrl+C or because a thread has called Quarkus.asyncExit()).

An example of what this looks like is below:

package com.acme;

import io.quarkus.runtime.Quarkus;
import io.quarkus.runtime.QuarkusApplication;
import io.quarkus.runtime.annotations.QuarkusMain;

@QuarkusMain
public class Main {
    public static void main(String... args) {
        Quarkus.run(MyApp.class, args);
    }

    public static class MyApp implements QuarkusApplication {

        @Override
        public int run(String... args) throws Exception {
            System.out.println("Do startup logic here");
            Quarkus.waitForExit();
            return 0;
        }
    }
}

Quarkus.run also provides a version that allows the code to handle errors. For example:

package com.acme;

import io.quarkus.runtime.Quarkus;
import io.quarkus.runtime.QuarkusApplication;
import io.quarkus.runtime.annotations.QuarkusMain;

@QuarkusMain
public class Main {
    public static void main(String... args) {
        Quarkus.run(MyApp.class,
        (exitCode, exception) -> {
            // do whatever
        },
        args);
    }

    public static class MyApp implements QuarkusApplication {

        @Override
        public int run(String... args) throws Exception {
            System.out.println("Do startup logic here");
            Quarkus.waitForExit();
            return 0;
        }
    }
}

Injecting the command line arguments

It is possible to inject the arguments that were passed in on the command line:

@Inject
@CommandLineArguments
String[] args;

Command line arguments can be passed to the application through the -D flag with the property quarkus.args:

For Quarkus dev mode:

CLI

quarkus dev -Dquarkus.args=cmd-args

Maven

./mvnw quarkus:dev -Dquarkus.args=cmd-args

Gradle

./gradlew --console=plain quarkusDev -Dquarkus.args=cmd-args

For a runner jar: java -Dquarkus.args=<cmd-args> -jar target/quarkus-app/quarkus-run.jar
For a native executable: ./target/lifecycle-quickstart-1.0-SNAPSHOT-runner -Dquarkus.args=<cmd-args>

Listening for startup and shutdown events

Create a new class named AppLifecycleBean (or pick another name) in the org.acme.lifecycle package, and copy the following content:

package org.acme.lifecycle;

import jakarta.enterprise.context.ApplicationScoped;
import jakarta.enterprise.event.Observes;

import io.quarkus.runtime.ShutdownEvent;
import io.quarkus.runtime.StartupEvent;
import org.jboss.logging.Logger;

@ApplicationScoped
public class AppLifecycleBean {

    private static final Logger LOGGER = Logger.getLogger("ListenerBean");

    void onStart(@Observes StartupEvent ev) {               (1)
        LOGGER.info("The application is starting...");
    }

    void onStop(@Observes ShutdownEvent ev) {               (2)
        LOGGER.info("The application is stopping...");
    }

}

1	Method called when the application is starting
2	Method called when the application is terminating

The events are also called in dev mode between each redeployment.

The methods can access injected beans. Check the AppLifecycleBean.java class for details.

What is the difference from `@Initialized(ApplicationScoped.class)` and `@Destroyed(ApplicationScoped.class)`

In the JVM mode, there is no real difference, except that StartupEvent is always fired after @Initialized(ApplicationScoped.class) and ShutdownEvent is fired before @Destroyed(ApplicationScoped.class). For a native executable build, however, @Initialized(ApplicationScoped.class) is fired as part of the native build process, whereas StartupEvent is fired when the native image is executed. See Three Phases of Bootstrap and Quarkus Philosophy for more details.

In CDI applications, an event with qualifier @Initialized(ApplicationScoped.class) is fired when the application context is initialized. See the spec for more info.

Using `@Startup` to initialize a CDI bean at application startup

A bean represented by a class, producer method or field annotated with @Startup is initialized at application startup:

package org.acme.lifecycle;

import io.quarkus.runtime.Startup;
import jakarta.enterprise.context.ApplicationScoped;

@Startup (1)
@ApplicationScoped
public class EagerAppBean {

   private final String name;

   EagerAppBean(NameGenerator generator) { (2)
     this.name = generator.createName();
   }
}

1	For each bean annotated with `@Startup` a synthetic observer of `StartupEvent` is generated. The default priority is used.
2	The bean constructor is called when the application starts and the resulting contextual instance is stored in the application context.

@Dependent beans are destroyed immediately afterwards to follow the behavior of observers declared on @Dependent beans.

If a class is annotated with @Startup but with no scope annotation then @ApplicationScoped is added automatically.

The @Startup annotation can be also declared on a non-static non-producer no-args method:

package org.acme.lifecycle;

import io.quarkus.runtime.Startup;
import jakarta.enterprise.context.ApplicationScoped;

@ApplicationScoped
public class EagerAppBean {

   @Startup
   void init() { (1)
     doSomeCoolInit();
   }
}

1	The bean is created and the `init()` method is invoked upon the contextual instance when the application starts.

Using `@Shutdown` to execute a business method of a CDI bean during application shutdown

The @io.quarkus.runtime.Shutdown annotation is used to mark a business method of a CDI bean that should be executed during application shutdown. The annotated method must be non-private and non-static and declare no arguments. The behavior is similar to a declaration of a ShutdownEvent observer. The following examples are functionally equivalent.

import io.quarkus.runtime.Shutdown;
import io.quarkus.runtime.ShutdownEvent;
import jakarta.enterprise.context.ApplicationScoped;

@ApplicationScoped
class Bean1 {
   void onShutdown(@Observes ShutdownEvent event) {
      // place the logic here
   }
}

@ApplicationScoped
class Bean2 {

   @Shutdown
   void shutdown() {
      // place the logic here
   }
}

Package and run the application

Run the application with:

CLI

quarkus dev

Maven

./mvnw quarkus:dev

Gradle

./gradlew --console=plain quarkusDev

The logged message is printed. When the application is stopped, the second log message is printed.

As usual, the application can be packaged using:

CLI

quarkus build

Maven

./mvnw install

Gradle

./gradlew build

and executed using java -jar target/quarkus-app/quarkus-run.jar.

You can also generate the native executable using:

CLI

quarkus build --native

Maven

./mvnw install -Dnative

Gradle

./gradlew build -Dquarkus.native.enabled=true

Launch Modes

Quarkus has 3 different launch modes, NORMAL (i.e. production), DEVELOPMENT and TEST. If you are running quarkus:dev then the mode will be DEVELOPMENT, if you are running a JUnit test it will be TEST, otherwise it will be NORMAL.

Your application can get the launch mode by injecting the io.quarkus.runtime.LaunchMode enum into a CDI bean, or by invoking the static method io.quarkus.runtime.LaunchMode.current().

Graceful Shutdown

Quarkus includes support for graceful shutdown, this allows Quarkus to wait for running requests to finish, up till a set timeout. By default, this is disabled, however you can configure this by setting the quarkus.shutdown.timeout config property. When this is set shutdown will not happen until all running requests have completed, or until this timeout has elapsed.

Extensions that accept requests need to add support for this on an individual basis. At the moment only the HTTP extension supports this, so shutdown may still happen when messaging requests are active.

Quarkus supports a delay time, where the application instance still responds to requests, but the readiness probe fails. This gives the infrastructure time to recognize that the instance is shutting down and stop routing traffic to the instance. This feature can be enabled by setting the build-time property quarkus.shutdown.delay-enabled to true. The delay can then be configured by setting the runtime property quarkus.shutdown.delay. It is not set by default, thus no delay is applied.

To write duration values, use the standard java.time.Duration format. See the Duration#parse() javadoc for more information.

You can also use a simplified format, starting with a number:

If the value is only a number, it represents time in seconds.
If the value is a number followed by ms, it represents time in milliseconds.

In other cases, the simplified format is translated to the java.time.Duration format for parsing:

If the value is a number followed by h, m, or s, it is prefixed with PT.
If the value is a number followed by d, it is prefixed with P.

Prerequisites
Solution
Creating the Maven project
The main method
- Injecting the command line arguments
Listening for startup and shutdown events
Package and run the application
Launch Modes
Graceful Shutdown

Application Initialization and Termination

Prerequisites

Solution

Creating the Maven project

The main method

Injecting the command line arguments

Listening for startup and shutdown events

What is the difference from `@Initialized(ApplicationScoped.class)` and `@Destroyed(ApplicationScoped.class)`

Using `@Startup` to initialize a CDI bean at application startup

Using `@Shutdown` to execute a business method of a CDI bean during application shutdown

Package and run the application

Launch Modes

Graceful Shutdown

Related content

On the same extensions

Application Initialization and Termination

Prerequisites

Solution

Creating the Maven project

The main method

Injecting the command line arguments

Listening for startup and shutdown events

What is the difference from @Initialized(ApplicationScoped.class) and @Destroyed(ApplicationScoped.class)

Using @Startup to initialize a CDI bean at application startup

Using @Shutdown to execute a business method of a CDI bean during application shutdown

Package and run the application

Launch Modes

Graceful Shutdown

Related content

On the same extensions

What is the difference from `@Initialized(ApplicationScoped.class)` and `@Destroyed(ApplicationScoped.class)`

Using `@Startup` to initialize a CDI bean at application startup

Using `@Shutdown` to execute a business method of a CDI bean during application shutdown