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::page{title="Welcome to the Getting started with Open Liberty guide!"}

Learn how to develop a Java application on Open Liberty with Maven and Docker.

In this guide, you will use a pre-configured environment that runs in containers on the cloud and includes everything that you need to complete the guide.

This panel contains the step-by-step guide instructions. You can customize these instructions by using the toolbar at the top of this panel. Move between steps by using either the arrows or the buttons at the bottom of this panel.

The other panel displays the IDE that you will use to create files, edit the code, and run commands. This IDE is based on Visual Studio Code. It includes pre-installed tools and a built-in terminal.

::page{title="What you'll learn"}

You will learn how to run and update a simple REST microservice on Open Liberty. You will use Maven throughout the guide to build and deploy the microservice as well as to interact with the running Liberty instance.

Open Liberty is an open application framework designed for the cloud. It's small, lightweight, and designed with modern cloud-native application development in mind. It supports the full MicroProfile and Jakarta EE APIs and is composable, meaning that you can use only the features that you need, keeping everything lightweight, which is great for microservices. It also deploys to every major cloud platform, including Docker, Kubernetes, and Cloud Foundry.

Maven is an automation build tool that provides an efficient way to develop Java applications. Using Maven, you will build a simple microservice, called system, that collects basic system properties from your laptop and displays them on an endpoint that you can access in your web browser.

You'll also explore how to package your application with Open Liberty so that it can be deployed anywhere in one go. You will then make Liberty configuration and code changes and see how they are immediately picked up by a running instance.

Finally, you will package the application along with Liberty's configuration into a Docker image and run that image as a container.

::page{title="Getting started"}

To open a new command-line session, select Terminal > New Terminal from the menu of the IDE.

Run the following command to navigate to the /home/project directory:

cd /home/project

The fastest way to work through this guide is to clone the Git repository and use the projects that are provided inside:

git clone https://github.com/openliberty/guide-getting-started.git
cd guide-getting-started

The start directory contains the starting project that you will build upon.

The finish directory contains the finished project that you will build.

You have cloned a Maven project. To learn how to create a Liberty Maven project from scratch and edit your application using the Liberty Tools, see Developing a cloud-native Java application with Liberty Tools in IntelliJ IDEA.

In this IBM Cloud environment, you need to change the user home to /home/project by running the following command:

sudo usermod -d /home/project theia

::page{title="Building and running the application"}

Your application is configured to be built with Maven. Every Maven-configured project contains a pom.xml file, which defines the project configuration, dependencies, plug-ins, and so on.

Your pom.xml file is located in the start directory and is configured to include the liberty-maven-plugin, which allows you to install applications into Open Liberty and manage the associated Liberty instances.

To begin, navigate to the start directory. Build the system microservice that is provided and deploy it to Open Liberty by running the Maven liberty:run goal:

cd start
mvn liberty:run

The mvn command initiates a Maven build, during which the target directory is created to store all build-related files.

The liberty:run argument specifies the Open Liberty run goal, which starts an Open Liberty instance in the foreground. As part of this phase, an Open Liberty runtime is downloaded and installed into the target/liberty/wlp directory, an instance of Liberty is created and configured in the target/liberty/wlp/usr/servers/defaultServer directory, and the application is installed into that instance using loose config.

For more information about the Liberty Maven plug-in, see its GitHub repository.

When the Liberty instance begins starting up, various messages display in your command-line session. Wait for the following message, which indicates that Liberty's startup is complete:

[INFO] [AUDIT] CWWKF0011I: The server defaultServer is ready to run a smarter planet.

Open another command-line session by selecting Terminal > New Terminal from the menu of the IDE.

To access the system microservice, see the http://localhost:9080/system/properties URL, and you see a list of the various system properties of your JVM:

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/system/properties | jq
{
    "os.name": "Mac OS X",
    "java.version": "1.8.0_151",
    ...
}

When you need to stop the Liberty instance, press Ctrl+C in the command-line session where you ran Liberty, or run the liberty:stop goal from the start directory in another command-line session:

mvn liberty:stop

::page{title="Starting and stopping Open Liberty in the background"}

Although you can start and stop Liberty in the foreground by using the Maven liberty:run goal, you can also start and stop the Liberty instance in the background with the Maven liberty:start and liberty:stop goals:

mvn liberty:start
mvn liberty:stop

::page{title="Updating Liberty's configuration without restarting"}

The Open Liberty Maven plug-in includes a dev goal that listens for any changes in the project, including application source code or configuration. The Open Liberty instance automatically reloads the configuration without restarting. This goal allows for quicker turnarounds and an improved developer experience.

Stop the Open Liberty instance if it is running, and start it in dev mode by running the liberty:dev goal in the start directory:

mvn liberty:dev

Dev mode automatically picks up changes that you make to your application and allows you to run tests by pressing the enter/return key in the active command-line session. When you’re working on your application, rather than rerunning Maven commands, press the enter/return key to verify your change.

As before, you can see that the application is running by going to the http://localhost:9080/system/properties URL.

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/system/properties | jq

Now try updating Liberty's server.xml configuration file while the instance is running in dev mode. The system microservice does not currently include health monitoring to report whether the Liberty instance and the microservice that it runs are healthy. You can add health reports with the MicroProfile Health feature, which adds a /health endpoint to your application. If you try to access this endpoint now at the http://localhost:9080/health/ URL, you see a 404 error because the /health endpoint does not yet exist:

To see the output for this URL in the IDE, run the following command at a terminal:

curl http://localhost:9080/health/
Error 404: java.io.FileNotFoundException: SRVE0190E: File not found: /health

To add the MicroProfile Health feature to the Liberty instance, include the mpHealth feature in the server.xml.

Replace the Liberty server.xml configuration file.

To open the server.xml file in your IDE, select File > Open > guide-getting-started/start/src/main/liberty/config/server.xml, or click the following button

::openFile{path="/home/project/guide-getting-started/start/src/main/liberty/config/server.xml"}

<server description="Sample Liberty server">
    <featureManager>
        <feature>restfulWS-3.1</feature>
        <feature>jsonp-2.1</feature>
        <feature>jsonb-3.0</feature>
        <feature>cdi-4.0</feature>
        <feature>mpMetrics-5.1</feature>
        <feature>mpHealth-4.0</feature>
        <feature>mpConfig-3.1</feature>
    </featureManager>

    <variable name="http.port" defaultValue="9080"/>
    <variable name="https.port" defaultValue="9443"/>

    <webApplication location="guide-getting-started.war" contextRoot="/" />
    
    <mpMetrics authentication="false"/>


    <httpEndpoint host="*" httpPort="${http.port}" 
        httpsPort="${https.port}" id="defaultHttpEndpoint"/>

    <variable name="io_openliberty_guides_system_inMaintenance" value="false"/>
</server>

Click the :fa-copy: copy button to copy the code and press Ctrl+V or Command+V in the IDE to replace the code to the file.

After you make the file changes, Open Liberty automatically reloads its configuration. When enabled, the mpHealth feature automatically adds a /health endpoint to the application. You can see the instance being updated in the Liberty log displayed in your command-line session:

[INFO] [AUDIT] CWWKG0016I: Starting server configuration update.
[INFO] [AUDIT] CWWKT0017I: Web application removed (default_host): http://foo:9080/
[INFO] [AUDIT] CWWKZ0009I: The application io.openliberty.guides.getting-started has stopped successfully.
[INFO] [AUDIT] CWWKG0017I: The server configuration was successfully updated in 0.284 seconds.
[INFO] [AUDIT] CWWKT0016I: Web application available (default_host): http://foo:9080/health/
[INFO] [AUDIT] CWWKF0012I: The server installed the following features: [mpHealth-3.0].
[INFO] [AUDIT] CWWKF0008I: Feature update completed in 0.285 seconds.
[INFO] [AUDIT] CWWKT0016I: Web application available (default_host): http://foo:9080/
[INFO] [AUDIT] CWWKZ0003I: The application io.openliberty.guides.getting-started updated in 0.173 seconds.

Try to access the /health endpoint again by visiting the http://localhost:9080/health URL. You see the following JSON:

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/health | jq
{
    "checks":[],
    "status":"UP"
}

Now you can verify whether your Liberty instance is up and running.

::page{title="Updating the source code without restarting Liberty"}

The RESTful application that contains your system microservice runs in a Liberty instance from its .class file and other artifacts. Open Liberty automatically monitors these artifacts, and whenever they are updated, it updates the running instance without the need for the instance to be restarted.

Look at your pom.xml file.

Try updating the source code while Liberty is running in dev mode. At the moment, the /health endpoint reports whether the Liberty instance is running, but the endpoint doesn't provide any details on the microservices that are running inside of the instance.

MicroProfile Health offers health checks for both readiness and liveness. A readiness check allows third-party services, such as Kubernetes, to know if the microservice is ready to process requests. A liveness check allows third-party services to determine if the microservice is running.

Create the SystemReadinessCheck class.

Run the following touch command in your terminal

touch /home/project/guide-getting-started/start/src/main/java/io/openliberty/sample/system/SystemReadinessCheck.java

Then, to open the SystemReadinessCheck.java file in your IDE, select File > Open > guide-getting-started/start/src/main/java/io/openliberty/sample/system/SystemReadinessCheck.java, or click the following button

::openFile{path="/home/project/guide-getting-started/start/src/main/java/io/openliberty/sample/system/SystemReadinessCheck.java"}

package io.openliberty.sample.system;

import jakarta.enterprise.context.ApplicationScoped;

import jakarta.inject.Inject;
import jakarta.inject.Provider;

import org.eclipse.microprofile.config.inject.ConfigProperty;
import org.eclipse.microprofile.health.Readiness;
import org.eclipse.microprofile.health.HealthCheck;
import org.eclipse.microprofile.health.HealthCheckResponse;

@Readiness
@ApplicationScoped
public class SystemReadinessCheck implements HealthCheck {

    private static final String READINESS_CHECK = SystemResource.class.getSimpleName()
                                                 + " Readiness Check";

    @Inject
    @ConfigProperty(name = "io_openliberty_guides_system_inMaintenance")
    Provider<String> inMaintenance;

    @Override
    public HealthCheckResponse call() {
        if (inMaintenance != null && inMaintenance.get().equalsIgnoreCase("true")) {
            return HealthCheckResponse.down(READINESS_CHECK);
        }
        return HealthCheckResponse.up(READINESS_CHECK);
    }

}

The SystemReadinessCheck class verifies that the system microservice is not in maintenance by checking a config property.

Create the SystemLivenessCheck class.

Run the following touch command in your terminal

touch /home/project/guide-getting-started/start/src/main/java/io/openliberty/sample/system/SystemLivenessCheck.java

Then, to open the SystemLivenessCheck.java file in your IDE, select File > Open > guide-getting-started/start/src/main/java/io/openliberty/sample/system/SystemLivenessCheck.java, or click the following button

::openFile{path="/home/project/guide-getting-started/start/src/main/java/io/openliberty/sample/system/SystemLivenessCheck.java"}

package io.openliberty.sample.system;

import jakarta.enterprise.context.ApplicationScoped;

import java.lang.management.MemoryMXBean;
import java.lang.management.ManagementFactory;

import org.eclipse.microprofile.health.Liveness;
import org.eclipse.microprofile.health.HealthCheck;
import org.eclipse.microprofile.health.HealthCheckResponse;

@Liveness
@ApplicationScoped
public class SystemLivenessCheck implements HealthCheck {

    @Override
    public HealthCheckResponse call() {
        MemoryMXBean memBean = ManagementFactory.getMemoryMXBean();
        long memUsed = memBean.getHeapMemoryUsage().getUsed();
        long memMax = memBean.getHeapMemoryUsage().getMax();

        return HealthCheckResponse.named(
            SystemResource.class.getSimpleName() + " Liveness Check")
                                  .status(memUsed < memMax * 0.9).build();
    }

}

The SystemLivenessCheck class reports a status of DOWN if the microservice uses over 90% of the maximum amount of memory.

After you make the file changes, Open Liberty automatically reloads its configuration and the system application.

The following messages display in your first command-line session:

[INFO] [AUDIT] CWWKT0017I: Web application removed (default_host): http://foo:9080/
[INFO] [AUDIT] CWWKZ0009I: The application io.openliberty.guides.getting-started has stopped successfully.
[INFO] [AUDIT] CWWKT0016I: Web application available (default_host): http://foo:9080/
[INFO] [AUDIT] CWWKZ0003I: The application io.openliberty.guides.getting-started updated in 0.136 seconds.

Access the /health endpoint again by going to the http://localhost:9080/health URL. This time you see the overall status of your Liberty instance and the aggregated data of the liveness and readiness checks for the system microservice:

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/health | jq
{  
   "checks":[  
      {  
         "data":{},
         "name":"SystemResource Readiness Check",
         "status":"UP"
      },
      {  
         "data":{},
         "name":"SystemResource Liveness Check",
         "status":"UP"
      }
   ],
   "status":"UP"
}

You can also access the /health/ready endpoint by going to the http://localhost:9080/health/ready URL to view the data from the readiness health check. Similarly, access the /health/live endpoint by going to the http://localhost:9080/health/live URL to view the data from the liveness health check.

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/health/ready | jq

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/health/live | jq

Making code changes and recompiling is fast and straightforward. Open Liberty dev mode automatically picks up changes in the .class files and artifacts, without needing to be restarted. Alternatively, you can run the run goal and manually repackage or recompile the application by using the mvn package command or the mvn compile command while Liberty is running. Dev mode was added to further improve the developer experience by minimizing turnaround times.

::page{title="Checking the Open Liberty logs"}

While Liberty is running in the foreground, it displays various console messages in the command-line session. These messages are also logged to the target/liberty/wlp/usr/servers/defaultServer/logs/console.log file. You can find the complete Liberty logs in the target/liberty/wlp/usr/servers/defaultServer/logs directory. The console.log and messages.log files are the primary log files that contain console output of the running application and the Liberty instance. More logs are created when runtime errors occur or whenever tracing is enabled. You can find the error logs in the ffdc directory and the tracing logs in the trace.log file.

In addition to the log files that are generated automatically, you can enable logging of specific Java packages or classes by using the logging element:

<logging traceSpecification="<component_1>=<level>:<component_2>=<level>:..."/>

The component element is a Java package or class, and the level element is one of the following logging levels: off, fatal, severe, warning, audit, info, config, detail, fine, finer, finest, all.

For more information about logging, see the Trace log detail levels, logging element, and Log and trace configuration documentation.

Try enabling detailed logging of the MicroProfile Health feature by adding the logging element to your configuration file.

Replace the Liberty server.xml configuration file.

To open the server.xml file in your IDE, select File > Open > guide-getting-started/start/src/main/liberty/config/server.xml, or click the following button

::openFile{path="/home/project/guide-getting-started/start/src/main/liberty/config/server.xml"}

<server description="Sample Liberty server">
    <featureManager>
        <feature>restfulWS-3.1</feature>
        <feature>jsonp-2.1</feature>
        <feature>jsonb-3.0</feature>
        <feature>cdi-4.0</feature>
        <feature>mpMetrics-5.1</feature>
        <feature>mpHealth-4.0</feature>
        <feature>mpConfig-3.1</feature>
    </featureManager>

    <variable name="http.port" defaultValue="9080"/>
    <variable name="https.port" defaultValue="9443"/>

    <webApplication location="guide-getting-started.war" contextRoot="/" />
    
    <mpMetrics authentication="false"/>

    <logging traceSpecification="com.ibm.ws.microprofile.health.*=all" />

    <httpEndpoint host="*" httpPort="${http.port}" 
        httpsPort="${https.port}" id="defaultHttpEndpoint"/>

    <variable name="io_openliberty_guides_system_inMaintenance" value="false"/>
</server>

After you change the file, Open Liberty automatically reloads its configuration.

Now, when you visit the /health endpoint, additional traces are logged in the trace.log file.

When you are done checking out the service, exit dev mode by pressing Ctrl+C in the command-line session where you ran Liberty.

::page{title="Running the application in a Docker container"}

To containerize the application, you need a Dockerfile. This file contains a collection of instructions that define how a Docker image is built, what files are packaged into it, what commands run when the image runs as a container, and other information. You can find a complete Dockerfile in the start directory. This Dockerfile copies the .war file into a Docker image that contains the Java runtime and a preconfigured Open Liberty runtime.

Run the mvn package command from the start directory so that the .war file resides in the target directory.

mvn package

To build and containerize the application, run the following Docker build command in the start directory:

docker build -t openliberty-getting-started:1.0-SNAPSHOT .

The Docker openliberty-getting-started:1.0-SNAPSHOT image is also built from the Dockerfile. To verify that the image is built, run the docker images command to list all local Docker images:

docker images

Your image should appear in the list of all Docker images:

REPOSITORY                     TAG             IMAGE ID        CREATED         SIZE
openliberty-getting-started    1.0-SNAPSHOT    85085141269b    21 hours ago    487MB

Next, run the image as a container:

docker run -d --name gettingstarted-app -p 9080:9080 openliberty-getting-started:1.0-SNAPSHOT

There is a bit going on here, so here's a breakdown of the command:

Flag Description
-d Runs the container in the background.
--name Specifies a name for the container.
-p Maps the container ports to the host ports.

The final argument in the docker run command is the Docker image name.

Next, run the docker ps command to verify that your container started:

docker ps

Make sure that your container is running and does not have Exited as its status:

CONTAINER ID    IMAGE                         CREATED          STATUS           NAMES
4294a6bdf41b    openliberty-getting-started   9 seconds ago    Up 11 seconds    gettingstarted-app

To access the application, go to the http://localhost:9080/system/properties URL.

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/system/properties | jq

To stop and remove the container, run the following commands:

docker stop gettingstarted-app && docker rm gettingstarted-app

To remove the image, run the following command:

docker rmi openliberty-getting-started:1.0-SNAPSHOT

::page{title="Developing the application in a Docker container"}

The Open Liberty Maven plug-in includes a devc goal that simplifies developing your application in a Docker container by starting dev mode with container support. This goal builds a Docker image, mounts the required directories, binds the required ports, and then runs the application inside of a container. Dev mode also listens for any changes in the application source code or configuration and rebuilds the image and restarts the container as necessary.

Build and run the container by running the devc goal from the start directory:

chmod 777 /home/project/guide-getting-started/start/target/liberty/wlp/usr/servers/defaultServer/logs
mvn liberty:devc -DserverStartTimeout=300

When you see the following message, Open Liberty is ready to run in dev mode:

**************************************************************
*    Liberty is running in dev mode.

Open another command-line session and run the docker ps command to verify that your container started:

docker ps

Your container should be running and have Up as its status:

CONTAINER ID        IMAGE                                 COMMAND                  CREATED             STATUS                         PORTS                                                                    NAMES
17af26af0539        guide-getting-started-dev-mode        "/opt/ol/helpers/run…"   3 minutes ago       Up 3 minutes                   0.0.0.0:7777->7777/tcp, 0.0.0.0:9080->9080/tcp, 0.0.0.0:9443->9443/tcp   liberty-dev

To access the application, go to the http://localhost:9080/system/properties URL.

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/system/properties | jq

Dev mode automatically picks up changes that you make to your application and allows you to run tests by pressing the enter/return key in the active command-line session.

Update the server.xml file to change the context root from / to /dev.

Replace the Liberty server.xml configuration file.

To open the server.xml file in your IDE, select File > Open > guide-getting-started/start/src/main/liberty/config/server.xml, or click the following button

::openFile{path="/home/project/guide-getting-started/start/src/main/liberty/config/server.xml"}

<server description="Sample Liberty server">
    <featureManager>
        <feature>restfulWS-3.1</feature>
        <feature>jsonp-2.1</feature>
        <feature>jsonb-3.0</feature>
        <feature>cdi-4.0</feature>
        <feature>mpMetrics-5.1</feature>
        <feature>mpHealth-4.0</feature>
        <feature>mpConfig-3.1</feature>
    </featureManager>

    <variable name="http.port" defaultValue="9080"/>
    <variable name="https.port" defaultValue="9443"/>

    <webApplication location="guide-getting-started.war" contextRoot="/dev" />
    <mpMetrics authentication="false"/>

    <logging traceSpecification="com.ibm.ws.microprofile.health.*=all" />

    <httpEndpoint host="*" httpPort="${http.port}" 
        httpsPort="${https.port}" id="defaultHttpEndpoint"/>

    <variable name="io_openliberty_guides_system_inMaintenance" value="false"/>
</server>

After you make the file changes, Open Liberty automatically reloads its configuration. When you see the following message in your command-line session, Open Liberty is ready to run again:

The server has been restarted.
************************************************************************
*    Liberty is running in dev mode.

Update the mpData.js file to change the url in the getSystemPropertiesRequest method to reflect the new context root.

Update the mpData.js file.

From the menu of the IDE, select File > Open > guide-getting-started/start/src/main/webapp/js/mpData.js, or click the following button

::openFile{path="/home/project/guide-getting-started/start/src/main/webapp/js/mpData.js"}

function getSystemPropertiesRequest() {
    var propToDisplay = ["java.vendor", "java.version", "user.name", "os.name", "wlp.install.dir", "wlp.server.name" ];
    var url = "http://localhost:9080/dev/system/properties";
    var req = new XMLHttpRequest();
    var table = document.getElementById("systemPropertiesTable");
    ...

Update the pom.xml file to change the context root from / to /dev in the maven-failsafe-plugin to reflect the new context root when you run functional tests.

Replace the pom.xml file.

To open the pom.xml file in your IDE, select File > Open > guide-getting-started/start/pom.xml, or click the following button

::openFile{path="/home/project/guide-getting-started/start/pom.xml"}

<?xml version='1.0' encoding='utf-8'?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>io.openliberty.guides</groupId>
    <artifactId>guide-getting-started</artifactId>
    <version>1.0-SNAPSHOT</version>
    <packaging>war</packaging>

    <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
        <project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
        <!-- Liberty configuration -->
        <liberty.var.http.port>9080</liberty.var.http.port>
        <liberty.var.https.port>9443</liberty.var.https.port>
    </properties>

    <dependencies>
        <!-- Provided dependencies -->
        <dependency>
            <groupId>jakarta.platform</groupId>
            <artifactId>jakarta.jakartaee-api</artifactId>
            <version>10.0.0</version>
            <scope>provided</scope>
        </dependency>
        <dependency>
            <groupId>org.eclipse.microprofile</groupId>
            <artifactId>microprofile</artifactId>
            <version>6.1</version>
            <type>pom</type>
            <scope>provided</scope>
        </dependency>
        <!-- For tests -->
        <dependency>
            <groupId>org.junit.jupiter</groupId>
            <artifactId>junit-jupiter</artifactId>
            <version>5.10.3</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.jboss.resteasy</groupId>
            <artifactId>resteasy-client</artifactId>
            <version>6.2.9.Final</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.jboss.resteasy</groupId>
            <artifactId>resteasy-json-binding-provider</artifactId>
            <version>6.2.9.Final</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>org.glassfish</groupId>
            <artifactId>jakarta.json</artifactId>
            <version>2.0.1</version>
            <scope>test</scope>
        </dependency>
    </dependencies>

    <build>
        <finalName>${project.artifactId}</finalName>
        <plugins>
            <!-- Enable liberty-maven plugin -->
            <plugin>
                <groupId>io.openliberty.tools</groupId>
                <artifactId>liberty-maven-plugin</artifactId>
                <version>3.10.3</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-war-plugin</artifactId>
                <version>3.4.0</version>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>3.3.0</version>
            </plugin>
            <!-- Plugin to run functional tests -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-failsafe-plugin</artifactId>
                <version>3.3.0</version>
                <configuration>
                    <systemPropertyVariables>
                        <http.port>${liberty.var.http.port}</http.port>
                        <context.root>/dev</context.root>
                    </systemPropertyVariables>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

You can run the tests by pressing the enter/return key from the command-line session where you started dev mode to verify your change.

You can access the application at the http://localhost:9080/dev/system/properties URL. Notice that the context root is now /dev.

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/dev/system/properties | jq

When you are finished, exit dev mode by pressing Ctrl+C in the command-line session that the container was started from. Exiting dev mode stops and removes the container. To check that the container was stopped, run the docker ps command.

::page{title="Running the application from a minimal runnable JAR"}

So far, Open Liberty was running out of the target/liberty/wlp directory, which effectively contains an Open Liberty installation and the deployed application. The final product of the Maven build is a server package for use in a continuous integration pipeline and, ultimately, a production deployment.

Open Liberty supports a number of different server packages. The sample application currently generates a usr package that contains the Liberty runtime and application to be extracted onto an Open Liberty installation.

Instead of creating a server package, you can generate a runnable JAR file that contains the application along with a Liberty runtime. This JAR file can then be run anywhere and deploy your application and runtime at the same time. To generate a runnable JAR file, override the include property:

mvn liberty:package -Dinclude=runnable

The packaging type is overridden from the usr package to the runnable package. This property then propagates to the liberty-maven-plugin plug-in, which generates the server package based on the openliberty-kernel package.

When the build completes, you can find the minimal runnable guide-getting-started.jar file in the target directory. This JAR file contains only the features that you explicitly enabled in your server.xml file. As a result, the generated JAR file is only about 50 MB.

To run the JAR file, first stop the Liberty instance if it's running. Then, navigate to the target directory and run the java -jar command:

java -jar guide-getting-started.jar

When Liberty starts, go to the http://localhost:9080/dev/system/properties URL to access your application that is now running out of the minimal runnable JAR file.

To see the output for this URL in the IDE, run the following command at a terminal:

curl -s http://localhost:9080/dev/system/properties | jq

You can stop the Liberty instance by pressing Ctrl+C in the command-line session that the instance runs in.

::page{title="Summary"}

Nice Work!

You've learned the basics of deploying and updating an application on Open Liberty.

Clean up your environment

Clean up your online environment so that it is ready to be used with the next guide:

Delete the guide-getting-started project by running the following commands:

cd /home/project
rm -fr guide-getting-started

What did you think of this guide?

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Or, click the Support/Feedback button in the IDE and select the Give feedback option. Fill in the fields, choose the General category, and click the Post Idea button.

What could make this guide better?

You can also provide feedback or contribute to this guide from GitHub.

Where to next?

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