Java fails to build

[catqwe]

Describe the bug
When I try to build the java implementation it fails with a long lst of errors, this is the first error:

buttplug-rs-ffi/lib/src/main/java/io/buttplug/MessageAttributes.java:3: error: package io.buttplug.protos does not exist
import io.buttplug.protos.ButtplugRsFfi;

The others might be triggered by this one or not.

Also at the end it says:
Deprecated Gradle features were used in this build, making it incompatible with Gradle 7.0.
This should also be addressed.

Expected behavior
It should just build when you run ./gradlew build

Actual behavior
The build fails.

Additional context
Used ./gradlew build command to build.