= HelloWorld :toc: :toc-placement!:

image:https://github.com/apache/causeway-app-helloworld/workflows/Build%20w/%20Maven%20+%20Jdk%208/badge.svg[] image:https://github.com/apache/causeway-app-helloworld/workflows/Build%20w/%20Maven%20+%20Jdk%2015/badge.svg[]

This is a minimal link:https://causeway.apache.org[Apache Causeway] application, intended as a starting point to learn what the framework is all about.

[TIP]

For real-world development, we recommend you instead start with the link:https://github.com/apache/causeway-app-simpleapp[SimpleApp] starter app.

It provides more structure and includes examples of fixtures, unit tests, integration tests, and BDD (Cucumber) specs.

toc::[]

== Quick start

• install prereqs:

** Java 11 LTS (eg link:https://adoptopenjdk.net/[Adopt OpenJDK] distribution) ** Maven 3.6 or later (http://maven.apache.org/download.cgi[download])

• download and unzip

[source,bash]

APP=helloworld BRANCH=master

REPO=causeway-app-$APP
curl "https://codeload.github.com/apache/$REPO/zip/$BRANCH" | jar xv
mv $REPO-$BRANCH $REPO
cd $REPO

• Build using Maven:

[source,bash]

mvn clean install

• Download the spring-instrument.jar for load-time weaving (discussed in more detail xref:#orm-support[below]):

[source,bash]

mvn dependency:get -DgroupId=org.springframework -DartifactId=spring-instrument -Dversion=XXX

Change "XXX" to the value that ${spring-framework.version} resolves to in the webapp pom.xml

• Run using Maven:

[source,bash]

mvn spring-boot:run

• Browse to http://localhost:8080.

• Login using:

** username: sven ** password: pass

The app runs with H2 running in-memory.

[#orm-support] == ORM Support

// EclipseLink : START

This version of the application uses EclipseLink JPA as its ORM, configured with load-time weaving. This requires that the application be run with a Java agent.

The spring-boot plugin is configured to run with this agent already. If you want to run from an IDE:

• first, you might wish to copy the file locally:

[source,bash]

cp ~/.m2/repository/org/springframework/spring-instrument/XXX/spring-instrument-XXX.jar lib/spring-instrument.jar

Change "XXX" to the value that ${spring-framework.version} resolves to in the webapp pom.xml

• Then specify the agent as a VM option:

[source,bash]

-javaagent:lib/spring-instrument.jar

// EclipseLink : END

// DataNucleus : START

//This version of the application uses DataNucleus as its ORM, which requires that any entities are "enhanced", a post-compile process. // //Normally this is done as part of a "mvn clean install", but the entities can also be enhanced explicity using: // //[source,bash] //---- //mvn -pl module-simple datanucleus:enhance -o //---- // //This is useful to know if the application or integration test fails to bootstrap, complaining of "unenhanced entities". // //TIP: You can also use enhance-all.sh

// DataNucleus : END