Clone flink repo to your Linux computer with below terminal commands

# Clone
$ git clone https://github.com/bauer/flink.git

Build protobuf with below terminal commands

# Change directory
$ cd flink/protobuf

# Clean project
flink/protobuf$ mvn clean

# Build project
flink/protobuf$ mvn clean install

The output is located in the target folder and is named bauer-protobuf-report-1.0-SNAPSHOT.jar

View generated java code in folder target/generated-sources/protobuf/java/io/github/bauerin file named ProtobufReport.java