# Matter Controller Java App Example

This is a Matter Controller Java app that can be used to commission and control
Matter accessory devices. It offers the following features: - Commission a
Matter device - Send echo requests to the Matter echo server - Send on/off
cluster requests to a Matter device

<hr>

-   [Matter Controller Java App Example](#matter-controller-java-app-example)
    -   [Requirements for building](#requirements-for-building)
    -   [Preparing for build](#preparing-for-build)
    -   [Building & Running the app](#building--running-the-app)

<hr>

## Requirements for building

You need to have the following two software installed on your Ubuntu system:

1. Java Runtime Environment (JRE)
2. Java Development Kit (JDK)

```shell
java -version
```

This will ensure either Java Runtime Environment is already installed on your
system or not. In order to install the Java Runtime Environment on your system,
run the following command as root:

```
sudo apt install default-jre Install Java default JRE
```

After installing the JRE, let us check if we have the Java Development Kit
installed on our system or not.

```shell
javac -version
```

The above output shows that I need to install the Java compiler or the JDK on my
system. You can install it through the following command as root:

```shell
sudo apt install default-jdk
```

You also need to install kotlin compiler on your Ubuntu system:

kotlin compiler version 1.8.10 or above is needed to compile
java-matter-controller, if you already have lower version kotlin compiler
installed on your Ubuntu from apt,  
you need to remove the Kotlin compiler package, run the following command:

```shell
sudo apt-get remove kotlin
```

Wait for the removal process to complete. Once it's done, the Kotlin compiler
will be removed from your system.

(Optional) If you want to remove any configuration files associated with Kotlin,
run the following command:

```shell
sudo apt-get purge kotlin
```

Install kotlin compiler 1.8.10 or above, such as
[kotlin-compiler-1.8.10-url](https://github.com/JetBrains/kotlin/releases/download/v1.8.10/kotlin-compiler-1.8.10.zip)

```shell
cd /usr/lib \
&& sudo wget -q [kotlin-compiler-1.8.10-url] \
&& sudo unzip kotlin-compiler-*.zip \
&& sudo rm kotlin-compiler-*.zip \
&& sudo rm -f kotlinc/bin/*.bat
```

Add a directory to PATH permanently by editing the `.bashrc` file located in the
Home directory. Follow these steps:

1. Open the `.bashrc` file using a text editor.
2. Go to the end of the file.
3. Paste the export syntax at the end of the file.

```shell
export PATH="/usr/lib/kotlinc/bin:$PATH"
```

### Linux

```shell
export JAVA_PATH=[JDK path]
```

<hr>

## Preparing for build

Complete the following steps to prepare the Matter build:

1. Check out the Matter repository.

2. Run bootstrap (**only required first time**)

    ```shell
    source scripts/bootstrap.sh
    ```

## Building & Running the app

This is the simplest option. In the command line, run the following command from
the top Matter directory:

```shell
./scripts/build/build_examples.py --target linux-x64-java-matter-controller build
```

The Java executable file `java-matter-controller` will be generated at
`out/linux-x64-java-matter-controller/bin/`

Run the java-matter-controller

```shell
java -Djava.library.path=../lib/jni -jar java-matter-controller
```