Quarkus: Modernize “helloworld” JBoss EAP quickstart, Part 1

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Quarkus: Modernize “helloworld” JBoss EAP quickstart, Part 1

Quarkus is, in its own words, “Supersonic subatomic Java” and a “Kubernetes native Java stack tailored for GraalVM & OpenJDK HotSpot, crafted from the best of breed Java libraries and standards.” For the purpose of illustrating how to modernize an existing Java application to Quarkus, I will use the Red Hat JBoss Enterprise Application Platform (JBoss EAP) quickstarts

Code:

helloworld

quickstart as sample of a Java application builds using technologies (CDI and Servlet 3) supported in Quarkus.

It’s important to note that both Quarkus and JBoss EAP rely on providing developers with tools based—as much as possible—on standards. If your application is not already running on JBoss EAP, there’s no problem. You can migrate it from your current application server to JBoss EAP using the Red Hat Application Migration Toolkit. After that, the final and working modernized version of the code is available in the https://github.com/mrizzi/jboss-eap-quic...ee/quarkus repository inside the

Code:

helloworld

module.

This article is based on the guides Quarkus provides, mainly Creating Your First Application and Building a Native Executable.

Get the code

To start, clone the JBoss EAP quickstarts repository locally, running:

Code:

$ git clone https://github.com/jboss-developer/jboss-eap-quickstarts.git Cloning into 'jboss-eap-quickstarts'... remote: Enumerating objects: 148133, done. remote: Total 148133 (delta 0), reused 0 (delta 0), pack-reused 148133 Receiving objects: 100% (148133/148133), 59.90 MiB | 7.62 MiB/s, done. Resolving deltas: 100% (66476/66476), done. $ cd jboss-eap-quickstarts/helloworld/

Try plain, vanilla

Code:

helloworld

The name of the quickstart is a strong clue about what this application does, but let’s follow a scientific approach in modernizing this code, so first things first: Try the application as it is.

Deploy

Code:

helloworld

1. Open a terminal and navigate to the root of the JBoss EAP directory
   Code:

   EAP_HOME
   (which you can download).
   
   
2. Start the JBoss EAP server with the default profile by typing the following command:
   

Code:

$ EAP_HOME/bin/standalone.sh

Note: For Windows, use the

Code:

EAP_HOME\bin\standalone.bat

script.

After a few seconds, the log should look like:

Code:

[org.jboss.as] (Controller Boot Thread) WFLYSRV0025: JBoss EAP 7.2.0.GA (WildFly Core 6.0.11.Final-redhat-00001) started in 3315ms - Started 306 of 527 services (321 services are lazy, passive or on-demand)

1. Open
   Code:

   http://127.0.0.1:8080
   in a browser, and a page like Figure 1 should appear:
   

Figure 1: The JBoss EAP home page.

1. Following instructions from Build and Deploy the Quickstart, deploy the
   Code:

   helloworld
   quickstart and execute (from the project root directory) the command:
   

Code:

$ mvn clean install wildfly:deploy

This command should end successfully with a log like this:

Code:

[INFO] ------------------------------------------------------------------------ [INFO] BUILD SUCCESS [INFO] ------------------------------------------------------------------------ [INFO] Total time: 8.224 s

The

Code:

helloworld

application has now been deployed for the first time in JBoss EAP in about eight seconds.

Test

Code:

helloworld

Following the Access the Application guide, open

Code:

http://127.0.0.1:8080/helloworld

 in the browser and see the application page, as shown in Figure 2:



Figure 2: JBoss EAP’s Hello World.

Make changes

Change the

Code:

createHelloMessage(String name)

input parameter from

Code:

World

to

Code:

Marco

(my ego is cheap):

Code:

writer.println("<h1>" + helloService.createHelloMessage("Marco") + "</h1>");

Execute again the command:

Code:

$ mvn clean install wildfly:deploy

and then refresh the web page in the browser to check the message displayed changes, as shown in Figure 3:



Figure 3: JBoss EAP’s Hello Marco.

Undeploy

Code:

helloworld

and shut down

If you want to undeploy (optional) the application before shutting down JBoss EAP, run the following command:

Code:

$ mvn clean install wildfly:undeploy

To shut down the JBoss EAP instance, enter Ctrl+C in the terminal where it’s running.

Let’s modernize

Code:

helloworld

Now we can leave the original

Code:

helloworld

behind and update it.

Create a new branch

Create a new working branch once the quickstart project finishes executing:

Code:

$ git checkout -b quarkus 7.2.0.GA

Change the 

Code:

pom.xml

file

The time has come to start changing the application. starting from the

Code:

pom.xml

file. From the

Code:

helloworld

folder, run the following command to let Quarkus add XML blocks:

Code:

$ mvn io.quarkus:quarkus-maven-plugin:0.23.2:create

This article uses the 0.23.2 version. To know which is the latest version is, please refer to https://github.com/quarkusio/quarkus/releases/latest/, since the Quarkus release cycles are short.

This command changed the

Code:

pom.xml

, file adding:

• The property
  Code:

  <quarkus.version>
  to define the Quarkus version to be used.
  
  
• The
  Code:

  <dependencyManagement>
  block to import the Quarkus bill of materials (BOM). In this way, there’s no need to add the version to each Quarkus dependency.
  
  
• The
  Code:

  quarkus-maven-plugin
  plugin responsible for packaging the application, and also providing the development mode.
  
  
• The
  Code:

  native
  profile to create application native executables.
  

Further changes required to

Code:

pom.xml

, to be done manually:

1. Move the 
   Code:

   <groupId>
   tag outside of the 
   Code:

   <parent>
   block, and above the
   Code:

   <artifactId>
   tag. Because we remove the
   Code:

   <parent>
   block in the next step, the
   Code:

   <groupId>
   must be preserved.
   
   
2. Remove the 
   Code:

   <parent>
   block: The application doesn’t need the JBoss parent pom anymore to run with Quarkus.
   
   
3. Add the 
   Code:

   <version>
   tag (below the 
   Code:

   <artifactId>
   tag) with the value you prefer.
   
   
4. Remove the 
   Code:

   <packaging>
   tag: The application won’t be a WAR anymore, but a plain JAR.
   
   
5. Change the following dependencies:
   
   1. Replace the
      Code:

      javax.enterprise:cdi-api
      dependency with
      Code:

      io.quarkus:quarkus-arc
      , removing 
      Code:

      <scope>provided</scope>
       because—as stated in the documentation—this Quarkus extension provides the CDI dependency injection.
      
      
   2. Replace the
      Code:

      org.jboss.spec.javax.servlet:jboss-servlet-api_4.0_spec
      dependency with
      Code:

      io.quarkus:quarkus-undertow
      , removing the
      Code:

      <scope>provided</scope>
      , because—again as stated in the documentation—this is the Quarkus extension that provides support for servlets.
      
      
   3. Remove the
      Code:

      org.jboss.spec.javax.annotation:jboss-annotations-api_1.3_spec
      dependency because it’s coming with the previously changed dependencies.
      

The

Code:

pom.xml

file’s fully changed version is available at https://github.com/mrizzi/jboss-eap-quic...ld/pom.xml.

Note that the above

Code:

mvn io.quarkus:quarkus-maven-plugin:0.23.2:create

command, besides the changes to the

Code:

pom.xml

file, added components to the project. The added file and folders are:

• The files
  Code:

  mvnw
  and 
  Code:

  mvnw.cmd
  , and
  Code:

  .mvn
  folder: The Maven Wrapper allows you to run Maven projects with a specific version of Maven without requiring that you install that specific Maven version.
  
  
• The
  Code:

  docker
  folder (in
  Code:

  src/main/
  ): This folder contains example 
  Code:

  Dockerfile
  files for both
  Code:

  native
  and
  Code:

  jvm
  modes (together with a 
  Code:

  .dockerignore
  file).
  
  
• The
  Code:

  resources
  folder (in
  Code:

  src/main/
  ): This folder contains an empty
  Code:

  application.properties
  file and the sample Quarkus landing page
  Code:

  index.html
  (more in the section “Run the modernized
  Code:

  helloworld
  “).
  

Run

Code:

helloworld

To test the application, use 

Code:

quarkus:dev

, which runs Quarkus in development mode (more details on Development Mode here).

Note: We expect this step to fail as changes are still required to the application, as detailed in this section.

Now run the command to check if and how it works:

Code:

$ ./mvnw compile quarkus:dev [INFO] Scanning for projects... [INFO] [INFO] ----------------< org.jboss.eap.quickstarts:helloworld >---------------- [INFO] Building Quickstart: helloworld quarkus [INFO] --------------------------------[ war ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ helloworld --- [INFO] Using 'UTF-8' encoding to copy filtered resources. [INFO] Copying 2 resources [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ helloworld --- [INFO] Nothing to compile - all classes are up to date [INFO] [INFO] --- quarkus-maven-plugin:0.23.2:dev (default-cli) @ helloworld --- Listening for transport dt_socket at address: 5005 INFO [io.qua.dep.QuarkusAugmentor] Beginning quarkus augmentation INFO [org.jbo.threads] JBoss Threads version 3.0.0.Final ERROR [io.qua.dev.DevModeMain] Failed to start quarkus: java.lang.RuntimeException: io.quarkus.builder.BuildException: Build failure: Build failed due to errors [error]: Build step io.quarkus.arc.deployment.ArcProcessor#validate threw an exception: javax.enterprise.inject.spi.DeploymentException: javax.enterprise.inject.UnsatisfiedResolutionException: Unsatisfied dependency for type org.jboss.as.quickstarts.helloworld.HelloService and qualifiers [@Default] - java member: org.jboss.as.quickstarts.helloworld.HelloWorldServlet#helloService - declared on CLASS bean [types=[javax.servlet.ServletConfig, java.io.Serializable, org.jboss.as.quickstarts.helloworld.HelloWorldServlet, javax.servlet.GenericServlet, javax.servlet.Servlet, java.lang.Object, javax.servlet.http.HttpServlet], qualifiers=[@Default, @Any], target=org.jboss.as.quickstarts.helloworld.HelloWorldServlet] at io.quarkus.arc.processor.BeanDeployment.processErrors(BeanDeployment.java:841) at io.quarkus.arc.processor.BeanDeployment.init(BeanDeployment.java:214) at io.quarkus.arc.processor.BeanProcessor.initialize(BeanProcessor.java:106) at io.quarkus.arc.deployment.ArcProcessor.validate(ArcProcessor.java:249) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at io.quarkus.deployment.ExtensionLoader$1.execute(ExtensionLoader.java:780) at io.quarkus.builder.BuildContext.run(BuildContext.java:415) at org.jboss.threads.ContextClassLoaderSavingRunnable.run(ContextClassLoaderSavingRunnable.java:35) at org.jboss.threads.EnhancedQueueExecutor.safeRun(EnhancedQueueExecutor.java:2011) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.doRunTask(EnhancedQueueExecutor.java:1535) at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1426) at java.lang.Thread.run(Thread.java:748) at org.jboss.threads.JBossThread.run(JBossThread.java:479) Caused by: javax.enterprise.inject.UnsatisfiedResolutionException: Unsatisfied dependency for type org.jboss.as.quickstarts.helloworld.HelloService and qualifiers [@Default] - java member: org.jboss.as.quickstarts.helloworld.HelloWorldServlet#helloService - declared on CLASS bean [types=[javax.servlet.ServletConfig, java.io.Serializable, org.jboss.as.quickstarts.helloworld.HelloWorldServlet, javax.servlet.GenericServlet, javax.servlet.Servlet, java.lang.Object, javax.servlet.http.HttpServlet], qualifiers=[@Default, @Any], target=org.jboss.as.quickstarts.helloworld.HelloWorldServlet] at io.quarkus.arc.processor.Beans.resolveInjectionPoint(Beans.java:428) at io.quarkus.arc.processor.BeanInfo.init(BeanInfo.java:371) at io.quarkus.arc.processor.BeanDeployment.init(BeanDeployment.java:206) ... 14 more

It failed. Why? What happened?

The

Code:

UnsatisfiedResolutionException

exception refers to the 

Code:

HelloService

class, which is a member of the

Code:

HelloWorldServlet

class (

Code:

java member: org.jboss.as.quickstarts.helloworld.HelloWorldServlet#helloService

). The problem is that

Code:

HelloWorldServlet

needs an injected instance of

Code:

HelloService

, but it can not be found (even if the two classes are in the very same package).

It’s time to return to Quarkus guides to leverage the documentation and understand how

Code:

@Inject

—and hence Contexts and Dependency Injection (CDI)—works in Quarkus, thanks to the Contexts and Dependency Injection guide. In the Bean Discovery paragraph, it says, “Bean classes that don’t have a bean defining annotation are not discovered.”

Looking at the 

Code:

HelloService

class, it’s clear there’s no bean defining annotation, and one has to be added to have Quarkus to discover the bean. So, because it’s a stateless object, it’s safe to add the

Code:

@ApplicationScoped

annotation:

Code:

@ApplicationScoped public class HelloService {

Note: The IDE should prompt you to add the required package shown here (add it manually if need be):

Code:

import javax.enterprise.context.ApplicationScoped;

If you’re in doubt about which scope to apply when the original bean has no scope defined, please refer to the JSR 365: Contexts and Dependency Injection for Java 2.0—Default scope documentation.

Now, try again to run the application, executing again the 

Code:

./mvnw compile quarkus:dev

command:

Code:

$ ./mvnw compile quarkus:dev [INFO] Scanning for projects... [INFO] [INFO] ----------------< org.jboss.eap.quickstarts:helloworld >---------------- [INFO] Building Quickstart: helloworld quarkus [INFO] --------------------------------[ war ]--------------------------------- [INFO] [INFO] --- maven-resources-plugin:2.6:resources (default-resources) @ helloworld --- [INFO] Using 'UTF-8' encoding to copy filtered resources. [INFO] Copying 2 resources [INFO] [INFO] --- maven-compiler-plugin:3.1:compile (default-compile) @ helloworld --- [INFO] Changes detected - recompiling the module! [INFO] Compiling 2 source files to /home/mrizzi/git/forked/jboss-eap-quickstarts/helloworld/target/classes [INFO] [INFO] --- quarkus-maven-plugin:0.23.2:dev (default-cli) @ helloworld --- Listening for transport dt_socket at address: 5005 INFO [io.qua.dep.QuarkusAugmentor] (main) Beginning quarkus augmentation INFO [io.qua.dep.QuarkusAugmentor] (main) Quarkus augmentation completed in 576ms INFO [io.quarkus] (main) Quarkus 0.23.2 started in 1.083s. Listening on: http://0.0.0.0:8080 INFO [io.quarkus] (main) Profile dev activated. Live Coding activated. INFO [io.quarkus] (main) Installed features: [cdi]

This time the application runs successfully.

Run the modernized

Code:

helloworld

As the terminal log suggests, open a browser to

Code:

http://0.0.0.0:8080

(the default Quarkus landing page), and the page shown in Figure 4 appears:



Figure 4: The Quarkus dev landing page.

This application has the following context’s definition in the

Code:

WebServlet

annotation:

Code:

@WebServlet("/HelloWorld") public class HelloWorldServlet extends HttpServlet {

Hence, you can browse to

Code:

http://0.0.0.0:8080/HelloWorld

to reach the page shown in Figure 5:



Figure 5: The Quarkus dev Hello World page.

It works!

Make changes

Please, pay attention to the fact that the

Code:

./mvnw compile quarkus:dev

command is still running, and we’re not going to stop it. Now, try to apply the same—very trivial—change to the code and see how Quarkus improves the developer experience:

Code:

writer.println("<h1>" + helloService.createHelloMessage("Marco") + "</h1>");

Save the file, and then refresh the web page to check that 

Code:

Hello Marco

appears, as shown in Figure 6:



Figure 6: The Quarkus dev Hello Marco page.

Take time to check the terminal output:

Code:

INFO [io.qua.dev] (vert.x-worker-thread-3) Changed source files detected, recompiling [/home/mrizzi/git/forked/jboss-eap-quickstarts/helloworld/src/main/java/org/jboss/as/quickstarts/helloworld/HelloWorldServlet.java] INFO [io.quarkus] (vert.x-worker-thread-3) Quarkus stopped in 0.003s INFO [io.qua.dep.QuarkusAugmentor] (vert.x-worker-thread-3) Beginning quarkus augmentation INFO [io.qua.dep.QuarkusAugmentor] (vert.x-worker-thread-3) Quarkus augmentation completed in 232ms INFO [io.quarkus] (vert.x-worker-thread-3) Quarkus 0.23.2 started in 0.257s. Listening on: http://0.0.0.0:8080 INFO [io.quarkus] (vert.x-worker-thread-3) Profile dev activated. Live Coding activated. INFO [io.quarkus] (vert.x-worker-thread-3) Installed features: [cdi] INFO [io.qua.dev] (vert.x-worker-thread-3) Hot replace total time: 0.371s

Refreshing the page triggered the source code change detection and the Quarkus automagic “stop-and-start.” All of this executed in just 0.371 seconds (that’s part of the Quarkus “Supersonic Subatomic Java” experience).

Build the

Code:

helloworld

packaged JAR

Now that the code works as expected, it can be packaged using the command:

Code:

$ ./mvnw clean package

This command creates two JARs in the

Code:

/target

folder. The first is 

Code:

helloworld-<version>.jar

, which is the standard artifact built from the Maven command with the project’s classes and resources. The second is 

Code:

helloworld-<version>-runner.jar

, which is an executable JAR.

Please pay attention to the fact that this is not an uber-jar, because all of the dependencies are copied into the

Code:

/target/lib

folder (and not bundled within the JAR). Hence, to run this JAR in another location or host, both the JAR file and the libraries in the

Code:

/lib

folder have to be copied, considering that the

Code:

Class-Path

entry of the

Code:

MANIFEST.MF

file in the JAR explicitly lists the JARs from the

Code:

lib

folder.

To create an uber-jar application, please refer to the Uber-Jar Creation Quarkus guide.

Run the

Code:

helloworld

packaged JAR

Now, the packaged JAR can be executed using the standard

Code:

java

command:

Code:

$ java -jar ./target/helloworld-<version>-runner.jar INFO [io.quarkus] (main) Quarkus 0.23.2 started in 0.673s. Listening on: http://0.0.0.0:8080 INFO [io.quarkus] (main) Profile prod activated. INFO [io.quarkus] (main) Installed features: [cdi]

As done above, open the

Code:

http://0.0.0.0:8080

URL in a browser, and test that everything works.

Build the

Code:

helloworld

quickstart-native executable

So far so good. The

Code:

helloworld

quickstart ran as a standalone Java application using Quarkus dependencies, but more can be achieved by adding a further step to the modernization path: Build a native executable.

Install GraalVM

First of all, the tools for creating the native executable have to be installed:

1. Download GraalVM 19.2.0.1 from https://github.com/oracle/graal/releases...m-19.2.0.1.
   
   
2. Untar the file using the command:
   

Code:

$ tar xvzf graalvm-ce-linux-amd64-19.2.0.1.tar.gz

1. Go to the
   Code:

   untar
   folder.
   
   
2. Execute the following to download and add the native image component:
   

Code:

$ ./bin/gu install native-image

1. Set the
   Code:

   GRAALVM_HOME
   environment variable to the folder created in step two, for example:
   

Code:

$ export GRAALVM_HOME={untar-folder}/graalvm-ce-19.2.0.1

)

More details and install instructions for other operating systems are available in Building a Native Executable—Prerequisites Quarkus guide.

Build the

Code:

helloworld

native executable

As stated in the Building a Native Executable—Producing a native executable Quarkus guide, “Let’s now produce a native executable for our application. It improves the startup time of the application and produces a minimal disk footprint. The executable would have everything to run the application including the ‘JVM’ (shrunk to be just enough to run the application), and the application.”

To create the native executable, the Maven

Code:

native

profile has to be enabled by executing:

Code:

$ ./mvnw package -Pnative

The build took me about 1:10 minutes and the result is the

Code:

helloworld-<version>-runner

file in the

Code:

/target

folder.

Run the

Code:

helloworld

native executable

The

Code:

/target/helloworld-<version>-runner

file created in the previous step. It’s executable, so running it is easy:

Code:

$ ./target/helloworld-<version>-runner INFO [io.quarkus] (main) Quarkus 0.23.2 started in 0.006s. Listening on: http://0.0.0.0:8080 INFO [io.quarkus] (main) Profile prod activated. INFO [io.quarkus] (main) Installed features: [cdi]

As done before, open the

Code:

http://0.0.0.0:8080

URL in a browser and test that everything is working.

Next steps

I believe that this modernization, even of a basic application, is the right way to approach a brownfield application using technologies available in Quarkus. This way, you can start facing the issues and tackling them to understand and learn how to solve them.

In part two of this series, I’ll look at how to capture memory consumption data in order to evaluate performance improvements, which is a fundamental part of the modernization process.

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