S3 Batch Operations can invoke a Lambda written in Java. This method of Lambda invocation uses special request and response models. A developer is likely to model the request and response data in Java based on the batch-ops-invoke-lambda documentation.
We could include the Request and Response models in this library. We could even add a little bit of logic to help create the Response model, because most of its data is derived from the Request.
Something like:
com.amazonaws.services.lambda.runtime.events.S3BatchOpRequest
com.amazonaws.services.lambda.runtime.events.S3BatchOpResponse