Getting set up for CorDapp development

Software requirements

Corda uses industry-standard tools:

  • Java 8 JVM - we require at least version 8u171, but do not currently support Java 9 or higher. We have tested with Oracle JDK, Amazon Corretto, and Red Hat’s OpenJDK builds. Please note that OpenJDK builds usually exclude JavaFX, which our GUI tools require.
  • IntelliJ IDEA - supported versions 2017.x and 2018.x (with Kotlin plugin version 1.2.71)
  • Gradle - we use 4.10 and the gradlew script in the project / samples directories will download it for you.

Please note:

  • Applications on Corda (CorDapps) can be written in any language targeting the JVM. However, Corda itself and most of the samples are written in Kotlin. Kotlin is an official Android language, and you can read more about why Kotlin is a strong successor to Java here. If you’re unfamiliar with Kotlin, there is an official getting started guide, and a series of Kotlin Koans
  • IntelliJ IDEA is recommended due to the strength of its Kotlin integration.
  • If an HA Bridge/Float deployment is required then a Zookeeper 3.5.4-Beta cluster will be required. Refer to Hot-cold deployment and Bridge configuration for more deployment information.

Following these software recommendations will minimize the number of errors you encounter, and make it easier for others to provide support. However, if you do use other tools, we’d be interested to hear about any issues that arise.

Set-up instructions

The instructions below will allow you to set up your development environment for running Corda and writing CorDapps. If you have any issues, please reach out on Stack Overflow or via our Slack channels.

The set-up instructions are available for the following platforms:

Windows

Warning

If you are using a Mac, Debian/Ubuntu or Fedora machine, please follow the Mac, Debian/Ubuntu or Fedora instructions instead.

Java

  1. Visit http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
  2. Scroll down to “Java SE Development Kit 8uXXX” (where “XXX” is the latest minor version number)
  3. Toggle “Accept License Agreement”
  4. Click the download link for jdk-8uXXX-windows-x64.exe (where “XXX” is the latest minor version number)
  5. Download and run the executable to install Java (use the default settings)
  6. Add Java to the PATH environment variable by following the instructions at https://docs.oracle.com/javase/7/docs/webnotes/install/windows/jdk-installation-windows.html#path
  7. Open a new command prompt and run java -version to test that Java is installed correctly

Git

  1. Visit https://git-scm.com/download/win
  2. Click the “64-bit Git for Windows Setup” download link.
  3. Download and run the executable to install Git (use the default settings)
  4. Open a new command prompt and type git --version to test that git is installed correctly

IntelliJ

  1. Visit https://www.jetbrains.com/idea/download/download-thanks.html?code=IIC
  2. Download and run the executable to install IntelliJ Community Edition (use the default settings)
  3. Ensure the Kotlin plugin in Intellij is updated to version 1.2.71

Download a sample project

  1. Open a command prompt
  2. Clone the CorDapp example repo by running git clone https://github.com/corda/cordapp-example
  3. Move into the cordapp-example folder by running cd cordapp-example
  4. Checkout the corresponding branch for Corda Enterprise 3.1 by running git checkout release-enterprise-V3 in the current directory

Resolve Corda Enterprise binaries

The Corda Enterprise binaries are not available in a publicly accessible Maven repository. Instead, the Corda Enterprise binaries will be made available to your organisation as a compressed tarball (corda-3.1-developer-pack.tar.gz). This tarball contains all of the Corda dependencies as they would appear in your local Maven repository located at C:\Documents and Settings\{your-username}\.m2.

To build CorDapps on development machines the Corda Enterprise binaries will need to be discoverable by Gradle. The build.gradle file on the cordapp-example release-enterprise-V3 branch includes instructions on how to allow Gradle to discover dependencies.

  1. Open cordapp-example\build.gradle
  2. Do any of the following to allow Gradle to resolve Corda Enterprise binaries, for more information read the commented code in build.gradle:
    1. Add Corda Enterprise binaries and dependencies to your local maven repository path (e.g., C:\Documents and Settings\{your-username}\.m2).
    2. Upload Corda Enterprise binaries and dependencies to your company’s private Maven repository and register the repository with Gradle.
    3. Add Corda Enterprise binaries to a local directory and register a local Maven repository pointing to this directory with Gradle.

Note

Upon receiving the binaries, the quickest way to get started developing your CorDapps is option a. This can be done by firstly unpacking the corda-3.1-developer-pack.tar.gz compressed tarball. Then, copy the unpacked respository folder to your local Maven repository located at C:\Documents and Settings\{your-username}\.m2.

Run from the command prompt

  1. Move into the cordapp-example folder by running cd cordapp-example
  2. From the cordapp-example folder, deploy the nodes by running gradlew deployNodes
  3. Start the nodes by running call kotlin-source/build/nodes/runnodes.bat
  4. Wait until all the terminal windows display either Webserver started up in XX.X sec or Node for "NodeC" started up and registered in XX.XX sec
  5. Confirm that the CorDapp is running correctly by visiting the front end at http://localhost:10009/web/example/

Run from IntelliJ

  1. Open IntelliJ Community Edition
  2. On the splash screen, click Open (do not click Import Project) and select the cordapp-example folder

Warning

If you click Import Project instead of Open, the project’s run configurations will be erased!

  1. Once the project is open, click File, then Project Structure. Under Project SDK:, set the project SDK by clicking New..., clicking JDK, and navigating to C:\\Program Files\\Java\\jdk1.8.0_XXX (where XXX is the latest minor version number). Click OK
  2. Again under File then Project Structure, select Modules. Click +, then Import Module, then select the cordapp-example folder and click Open. Choose to Import module from external model, select Gradle, click Next then Finish (leaving the defaults) and OK
  3. Wait for the indexing to finish (a progress bar will display at the bottom-right of the IntelliJ window until indexing is complete)
  4. At the top-right of the screen, to the left of the green play arrow, you should see a dropdown. In that dropdown, select Run Example Cordapp - Kotlin and click the green play arrow.
  5. Wait until the run windows displays the message Webserver started up in XX.X sec
  6. Confirm that the CorDapp is running correctly by visiting the front end at `http://localhost:10009/web/example/

Mac

Warning

If you are using a Windows, Debian/Ubuntu or Fedora machine, please follow the Windows, Debian/Ubuntu or Fedora instructions instead.

Java

  1. Visit http://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html
  2. Scroll down to “Java SE Development Kit 8uXXX” (where “XXX” is the latest minor version number)
  3. Toggle “Accept License Agreement”
  4. Click the download link for jdk-8uXXX-macosx-x64.dmg (where “XXX” is the latest minor version number)
  5. Download and run the executable to install Java (use the default settings)
  6. Open a new terminal window and run java -version to test that Java is installed correctly. The version should be “8u171” or higher.

IntelliJ

  1. Visit https://www.jetbrains.com/idea/download/download-thanks.html?platform=mac&code=IIC
  2. Download and run the executable to install IntelliJ Community Edition (use the default settings)
  3. Ensure the Kotlin plugin in Intellij is updated to version 1.2.71

Download a sample project

  1. Open a terminal
  2. Clone the CorDapp example repo by running git clone https://github.com/corda/cordapp-example
  3. Move into the cordapp-example folder by running cd cordapp-example
  4. Checkout the corresponding branch for Corda Enterprise 3.1 by running git checkout release-enterprise-V3 in the current directory

Resolve Corda Enterprise binaries

The Corda Enterprise binaries are not available in a publicly accessible Maven repository. Instead, the Corda Enterprise binaries will be made available to your organisation as a compressed tarball (corda-3.1-developer-pack.tar.gz). This tarball contains all of the Corda dependencies as they would appear in your local Maven repository located at ~/.m2/repository.

To build CorDapps on development machines the Corda Enterprise binaries will need to be discoverable by Gradle. The build.gradle file on the cordapp-example release-enterprise-V3 branch includes instructions on how to allow Gradle to discover dependencies.

  1. Open cordapp-example/build.gradle
  2. Do any of the following to allow Gradle to resolve Corda Enterprise binaries, for more information read the commented code in build.gradle:
    1. Add Corda Enterprise binaries and dependencies to your local maven repository path e.g., ~/.m2/repository
    2. Upload Corda Enterprise binaries and dependencies to your company’s private Maven repository and register the repository with Gradle.
    3. Add Corda Enterprise binaries to a local directory and register a local Maven repository pointing to this directory with Gradle.

Note

Upon receiving the binaries, the quickest way to get started developing your CorDapps is option a. This can

be done by firstly unpacking the corda-3.1-developer-pack.tar.gz compressed tarball:

tar -xvzf corda-3.1-developer-pack.tar.gz

Then, copy the unpacked respository folder to your local Maven repository:

rsync -av repository ~/.m2/

The extracted folder can now be deleted:

rm -rf repository

Run from the terminal

  1. Move into the cordapp-example folder by running cd cordapp-example
  2. From the cordapp-example folder, deploy the nodes by running ./gradlew deployNodes
  3. Start the nodes by running kotlin-source/build/nodes/runnodes. Do not click while 7 additional terminal windows start up.
  4. Wait until all the terminal windows display either Webserver started up in XX.X sec or Node for "NodeC" started up and registered in XX.XX sec
  5. Confirm that the CorDapp is running correctly by visiting the front end at http://localhost:10009/web/example/

Run from IntelliJ

  1. Open IntelliJ Community Edition
  2. On the splash screen, click Open (do not click Import Project) and select the cordapp-example folder

Warning

If you click Import Project instead of Open, the project’s run configurations will be erased!

  1. Once the project is open, click File, then Project Structure. Under Project SDK:, set the project SDK by clicking New..., clicking JDK, and navigating to your JDK installation (e.g., /Library/Java/JavaVirtualMachines/jdk1.8.0_XXX.jdk, where XXX is the latest minor version number). Click OK
  2. Again under File then Project Structure, select Modules. Click +, then Import Module, then select the cordapp-example folder and click Open. Choose to Import module from external model, select Gradle, click Next then Finish (leaving the defaults) and OK
  3. Wait for the indexing to finish (a progress bar will display at the bottom-right of the IntelliJ window until indexing is complete)
  4. At the top-right of the screen, to the left of the green play arrow, you should see a dropdown. In that dropdown, select Run Example Cordapp - Kotlin and click the green play arrow.
  5. Wait until the run windows displays the message Webserver started up in XX.X sec
  6. Confirm that the CorDapp is running correctly by visiting the front end at http://localhost:10009/web/example/

CorDapp Templates and samples

A CorDapp template that you can use as the basis for your own CorDapps is available in both Java and Kotlin versions:

And a list of simple sample CorDapps for you to explore basic concepts is available here:

You can clone these repos to your local machine by running the command git clone [repo URL].

Debian/Ubuntu

Warning

If you are using a Mac, Windows or Fedora machine, please follow the Mac, Windows or Fedora instructions instead.

These instructions were tested on Ubuntu Desktop 18.04 LTS.

Java

  1. Open a new terminal and add the Oracle PPA to your repositories by typing sudo add-apt-repository ppa:webupd8team/java. Press ENTER when prompted.
  2. Update your packages list with the command sudo apt update
  3. Install the Oracle JDK 8 by typing sudo apt install oracle-java8-installer. Press Y when prompted and agree to the licence terms.
  4. Verify that the JDK was installed correctly by running java -version

Git

  1. From the terminal, Git can be installed using apt with the command sudo apt install git
  2. Verify that git was installed correctly by typing git --version

IntelliJ

Jetbrains offers a pre-built snap package that allows for easy, one-step installation of IntelliJ onto Ubuntu.

  1. To download the snap, navigate to https://snapcraft.io/intellij-idea-community
  2. Click Install, then View in Desktop Store. Choose Ubuntu Software in the Launch Application window.
  3. Ensure the Kotlin plugin in Intellij is updated to version 1.2.71

Fedora

Warning

If you are using a Mac, Windows or Debian/Ubuntu machine, please follow the Mac, Windows or Debian/Ubuntu instructions instead.

These instructions were tested on Fedora 28.

Java

  1. Download the RPM installation file of Oracle JDK from https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html.
  2. Install the package with rpm -ivh jdk-<version>-linux-<architecture>.rpm or use the default software manager.
  3. Choose java version by using the following command alternatives --config java
  4. Verify that the JDK was installed correctly by running java -version

Git

  1. From the terminal, Git can be installed using dnf with the command sudo dnf install git
  2. Verify that git was installed correctly by typing git --version

IntelliJ

  1. Visit https://www.jetbrains.com/idea/download/download-thanks.html?platform=linux&code=IIC
  2. Unpack the tar.gz file using the following command tar xfz ideaIC-<version>.tar.gz -C /opt
  3. Run IntelliJ with /opt/ideaIC-<version>/bin/idea.sh
  4. Ensure the Kotlin plugin in IntelliJ is updated to version 1.2.71

Next steps

The best way to check that everything is working fine is by taking a deeper look at the example CorDapp.

Next, you should read through Corda Key Concepts to understand how Corda works.

By then, you’ll be ready to start writing your own CorDapps. Learn how to do this in the Hello, World tutorial. You may want to refer to the API documentation, the flow cookbook and the samples along the way.

If you encounter any issues, please ask on Stack Overflow or via our Slack channels.