Install Open JDK 15 if not already installed.

sudo mv openjdk-15_osx-x64_bin.tar.gz /Library/Java/JavaVirtualMachines/
cd /Library/Java/JavaVirtualMachines/
sudo tar -xzf openjdk-15_osx-x64_bin.tar.gz
sudo rm openjdk-15_osx-x64_bin.tar.gz

Use /usr/libexec/java_home to set JAVA_HOME and PATH environment variables in .bash_profile (or where appropriate).

If you haven't installed rust android targets first add those to your environment using rustup

rustup target add x86_64-apple-darwin x86_64-unknown-linux-gnu x86_64-linux-android aarch64-linux-android armv7-linux-androideabi i686-linux-android

Then make sure that you have an Android NDK installed (preferably the latest one), and that you have an NDK_HOME env variable set before you start building the library. Usually, if installed through the sdkmanager, your NDK_HOME will look more or less like this: /home/user/Android/Sdk/ndk/<version>/.

Build android library in .aar format with:

./gradlew build

Gradle will build automatically the native library with rust for all 4 platforms using NDK. You can choose to build only for a specific platform by setting the env variable BUILD_TARGETS to a comma-separated list containing one or more of the following items:

• aarch64
• armv7
• x86_64
• i686

The output aar library is available at ./library/build/outputs/aar.

Then you can run the tests with:

./gradlew connectedDebugAndroidTest

If you only want to build the native library, maybe for one single platform, you can do so with something like:

CARGO_TARGET_AARCH64_LINUX_ANDROID_LINKER="aarch64-linux-android21-clang" CC="aarch64-linux-android21-clang" cargo build --target=aarch64-linux-android

Make sure that the compiler from the NDK is in your PATH

If the library is built in debug mode, there should already be a symlink from ./target/debug//libbdk_jni.so to the jniLibs directory, otherwise manually copy the shared object.

Use the below command to publish the .aar files generated by this project to your local maven2 repository (~/.r2/repository):

```script
./gradlew publishToMavenLocal
```

Once published you will see two new artifacts in your local maven repository:

~/.m2/repository/org/bitcoindevkit/bdkjni/bdk-jni-debug/<version>/bdk-jni-debug-<version>.aar
~/.m2/repository/org/bitcoindevkit/bdkjni/bdk-jni/<version>/bdk-jni-<version>.aar

You can then include the bdk.aar or bdk-debug.aar library in a local Android project by first adding mavenLocal() to your build.gradle repositories section:

```
repositories {

   mavenLocal()
   ...
}
```

And then adding bdk-jni or bdk-jni-debug to your app/build.gradle dependencies:

```
dependencies {
   implementation 'org.bitcoindevkit.bdkjni:bdk-jni:0.1.0-beta.1'
   ...
}
```

Note: Once regular release builds are published to a public maven repository these steps will only be needed to test local development builds of bdk-jni.