Prepare your development environment (Java)

November 14, 2017 · View on GitHub

This document describes how to prepare your development environment to use the Azure IoT Edge for Java module development.

Java JDK SE
Maven 3
Azure IoT Edge for Java
- Build from source
Application Samples

## Install Java JDK SE To use Azure IoT Edge and run the samples you will need a **32-bit** installation of a **JDK** (it is insufficient to only have the JRE installed).

Windows

For downloads and installation instructions go here: http://www.oracle.com/technetwork/java/javase/downloads/index.html

Set up environment variables

Please make sure that the JAVA_HOME environment variable includes the full path to the jdk1.x.x directory. (Example: JAVA_HOME=C:\Program Files\Java\jdk1.8.0_92)
Please make sure that the PATH environment variable includes the full path to the jdk1.x.x\jre\bin directory. (Example: %JAVA_HOME%\bin)
Please make sure that the PATH environment variable includes the full path to the jdk1.x.x\jre\bin\server directory. (Example: %JAVA_HOME%\jre\bin\server)

You can test whether your PATH variable is set correctly by restarting your console and running java -version.

Linux

Depending on your Linux distribution, you can install the JDK using apt-get, alternatively, you may visit the link above to find the download and instructions for Linux x86.

Set up environment variables

Please make sure that the PATH environment variable includes the full path to the bin folder containing java as well as the server directory containing the jvm.
```
which java
echo $PATH
```
Ensure that the bin directory shown by the which java command matches one of the directories shown in your $PATH variable and that the server directory containing the jvm is present in your$ PATH. If it is not:
```
export PATH=/path/to/java/bin:$PATH
export PATH=/path/to/java/jre/lib/amd64/server:$PATH
```
Please make sure that the JAVA_HOME environment variable includes the full path to the jdk.
```
update-alternatives --config java
```
Take note of the jdk location. update-alternatives will show something similar to /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java. The jdk directory would then be /usr/lib/jvm/java-8-openjdk-amd64/.
```
export JAVA_HOME=/path/to/jdk
```

## Install Maven Using **_Maven 3_** is the recommended way to install the interfaces and classes for the Java binding mechanism for **Azure IoT Edge**.

Windows

For downloads and installation instructions go here: https://maven.apache.org/download.cgi

Set up environment variables

Please make sure that the PATH environment variable includes the full path to the apache-maven-3.x.x\bin directory. (Example: F:\Setups\apache-maven-3.3.3\bin). The apache-maven-3.x.x directory is where Maven 3 is installed.

You can verify that the environment variables necessary to run Maven 3 have been set correctly by restarting your console and running mvn --version.

Linux

On Linux, Maven 3 can be installed as follows:

sudo apt-get update
sudo apt-get install maven

Set up environment variables

Please verify the following:

Ensure the PATH environment variable contains the full path to the bin folder containing Maven 3.

which mvn
echo $PATH

Ensure that the bin directory shown by the which mvn command matches one of the directories shown in your $PATH variable. If it does not: ``` export PATH=/path/to/mvn/bin:$ PATH ```

You can verify that the environment variables necessary to run Maven 3 have been set correctly by running mvn --version.

## Install Azure IoT Edge

There are two ways to get the .jar library for the Java module binding for Azure IoT Edge. You may either download the source code and build on your machine, or include the project as a dependency in your project if your project is a Maven project. Both methods are described below.

### Build Java binding for Azure IoT Edge from sources - Get a copy of **Azure IoT Edge** from GitHub if you have not already done so. You should fetch a copy of the source from the **master** branch of the GitHub repository: - When you have obtained a copy of the source, you can build the binding for Java.

Open a command prompt and use the following commands for the steps above:

    git clone https://github.com/Azure/iot-edge.git
    cd iot-edge/bindings/java/gateway-java-binding
    mvn clean install

The compiled JAR file with all dependencies bundled in can then be found at:

{Azure IoT Edge root}/bindings/java/gateway-java-binding/target/gateway-java-binding-{version}.jar

When you're ready to build your own module in Java, include this JAR file in your project to get the interfaces and classes that you need.

## Sample applications

This repository contains a sample gateway that includes modules written in Java that illustrate how to write modules in Java and use Azure IoT Edge. For more information, see the readme.