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Getting Started on Linux

Get SAP Cloud SDK Development Environment for Java on Linux​

This tutorial will guide you through getting your SAP Cloud SDK development environment up and running on Linux. All the steps were verified on Ubuntu 18.04 and should comply with other Debian-based distributions.

Required Knowledge​

No initial knowledge is required.

Let's Install Dependencies​

Installing the Java Development Kit and Maven​

SAP Cloud SDK supports Java 8, Java 11 and Java 17.

I'll base this example on Java 8.

sudo apt-get install openjdk-8-jdk

Updating alternatives to make sure the right version of Java is used.

Your distribution might have a different version of Java installed by default. You can check your Java version by running:

java -version

As you can see below, my laptop has Java 11 as default.

openjdk 11.0.5 2019-10-15
OpenJDK Runtime Environment (build 11.0.5+10-post-Ubuntu-0ubuntu1.1)
OpenJDK 64-Bit Server VM (build 11.0.5+10-post-Ubuntu-0ubuntu1.1, mixed mode)

Check what Java versions you have on your machine with:

update-java-alternatives --list

After installing OpenJDK 8 you should now have both Java 8 and Java 11.

java-1.11.0-openjdk-amd64      1111       /usr/lib/jvm/java-1.11.0-openjdk-amd64
java-1.8.0-openjdk-amd64       1081       /usr/lib/jvm/java-1.8.0-openjdk-amd64

To switch between Java versions run:

sudo update-alternatives --config java

In my case, I have to press 2 to make Java 8 default.

Selection    Path                                            Priority   Status
------------------------------------------------------------
0            /usr/lib/jvm/java-11-openjdk-amd64/bin/java      1111      auto mode
*1            /usr/lib/jvm/java-11-openjdk-amd64/bin/java      1111      manual mode
2            /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java   1081      manual mode
Press <enter> to keep the current choice[*], or type selection number:

Check the Java version again. Mind, the version parameter has just one hyphen for Java 8 CLI.

java -version

You have now switched to Java 8.

openjdk version "1.8.0_232"
OpenJDK Runtime Environment (build 1.8.0_232-8u232-b09-0ubuntu1.1-b09)
OpenJDK 64-Bit Server VM (build 25.232-b09, mixed mode)

Use Maven To Build and Deploy Your App​

Install maven with:

sudo apt-get install maven

To check if maven is installed correctly run:

mvn --version

You'll see the maven version and build details.

Apache Maven 3.6.1
Maven home: /usr/share/maven
Java version: 1.8.0_232, vendor: Private Build, runtime: /usr/lib/jvm/java-8-openjdk-amd64/jre
Default locale: en_US, platform encoding: ANSI_X3.4-1968
OS name: "linux", version: "5.3.0-26-generic", arch: "amd64", family: "unix"

To find out more about Apache Maven, how to get it for your Linux distribution, and detailed tutorials follow the official maven documentation.

Cloud Foundry Command Line Interface​

To deploy your app developed with SAP Cloud SDK to SAP Business Technology Platform you'll need the Cloud Foundry command-line interface (CLI). You can download the latest release of the DEB package from the official CF GitHub repository or follow instructions to install it with you package manager: apt-get, yum and homebrew are supported.

After installing the CLI, you might need to reload your shell before it becomes available. To check if it works run:

cf

Installing IntelliJ Idea IDE​

For the best developer experience, we recommend getting the community version of IntelliJ Idea. Download the archive from the official site and follow installation instructions for your system.

info

Another supported IDE is Eclipse.

Initialize and Build Your App​

To Initialize Your SAP Cloud SDK App From the Maven Archetype​

mvn archetype:generate -DarchetypeGroupId=com.sap.cloud.sdk.archetypes -DarchetypeArtifactId=scp-cf-spring -DarchetypeVersion=RELEASE

The snippet above will create a Spring Boot app.

Building Your App​

Change the directory to the root of the app you've just created.

cd /<app-root-directory>

To build your APP run:

mvn clean package

After a successful build, you'll find a target folder within your app's root folder containing a war file along with other build artifacts. This war file is a packaged version of your web-app that's going to be deployed in the SAP Cloud Foundry environment.

Bind your Command-Line Interface to an API Endpoint​

Let's associate your Cloud Foundry(CF) CLI to your SAP account by providing an API endpoint and logging in with your account.

Select endpoint depending on your region:

To use a snippet for Europe run:

    cf api https://api.cf.eu10.hana.ondemand.com

Provide your credentials for the SAP BTP by running:

cf login

Deploying Your App​

To deploy your app run:

cf push

After a successful deployment, you'll see a status of just pushed app:

Waiting for app to start...
name:                test-app
requested state:     started
isolation segment:   trial
routes:              test-app-shy-hyena-st.cfapps.eu10.hana.ondemand.com
last uploaded:       Sun 12 Jan 14:29:02 CET 2020
stack:               cflinuxfs3
buildpacks:          sap_java_buildpack
type:            web
instances:       1/1
memory usage:    1024M
start command:   JRE_HOME="META-INF/.sap_java_buildpack/sapjvm" JBP_CONFIG_SAPJVM_MEMORY_STACK_THREADS="250" JBP_CLASSPATH="" JBP_CONFIG_SAPJVM_MEMORY_CLASS_COUNT="" JAVA_HOME="META-INF/.sap_java_buildpack/sapjvm"
JBP_CONFIG_SAPJVM_MEMORY_HEADROOM="0" CATALINA_HOME="META-INF/.sap_java_buildpack/tomee7" JAVA_OPTS=" -Djava.io.tmpdir=$TMPDIR -Dhttp.port=$PORT -Daccess.logging.enabled=false
-Dlogback.configurationFile=file:META-INF/.sap_java_buildpack/tomee7/conf/logback.xml -DSAPJVM_EXTENSION_COMMAND_HANDLER=com.sap.xs2rt.dropletaddon.JvmExtensionCommandHandler
-Djava.protocol.handler.pkgs=com.sap.xs.statistics.stream.handling.protocols -agentpath:/app/META-INF/.sap_java_buildpack/jvm_kill/jvmkill-1.12.0.RELEASE-trusty.so=printHeapHistogram=1 -Dsun.net.inetaddr.ttl=0
-Dsun.net.inetaddr.negative.ttl=0" ./META-INF/.sap_java_buildpack/tomee7/bin/catalina.sh run
state     since                  cpu     memory         disk           details
#0   running   2020-01-12T13:30:29Z   69.0%   446.2M of 1G   191.1M of 1G

To verify your deployment take a URL indicated in the routes section from the deployment output above. Put it into your browser and add /hello at the end. It should look similar to: https://test-app-shy-hyena-st.cfapps.eu10.hana.ondemand.com/hello.