You need to install the protoc compiler from
https://github.com/google/protobuf/releases
For linux/osx you download the .tar distro, and untar it, and then
sudo ./configure sudo ./make check sudo ./make install
If its succesful, you can type
protoc --version
To list the version of the proto compiler.
You then need to compile the sample test source for the camel-protobuf
component.
The sample test source is an example taken from the Protobuf Java tutorial at: https://developers.google.com/protocol-buffers/docs/javatutorial
cd components/camel-protobuf cd src/test/proto protoc --java_out=../java ./addressbook.proto
The generate source code will override the existing. You then need to insert back the checkstyle:off rule. For that take a git diff to see the code changes.