Please add example for PlayAssetDelivery java

I was trying to implement `Play Asset Delivery` for `java` from [here](https://developer.android.com/guide/app-bundle/asset-delivery/build-native-java). But then there were 2 problems with that:
1. Step number 9 [here](https://developer.android.com/guide/app-bundle/asset-delivery/build-native-java) didn't work for me. ( I am using ```classpath 'com.android.tools.build:gradle:4.0.0-rc01'``` and `distributionUrl=https\://services.gradle.org/distributions/gradle-6.2.2-bin.zip` in my project)
2. There was no error due to step1 but when I tried to get the asset from AssetManager it was throwing exception `java.io.FileNotFoundException: asset1.mp4`.
Please add code for reference.