unused_deps is a command line tool to determine any unused dependencies in java_library rules. targets. It outputs buildozer commands to apply the suggested prunings.
go get -u github.com/golang/protobuf/{proto,protoc-gen-go}gopath=$(go env GOPATH) cd $gopath/src/github.com/bazelbuild/buildtools/unused_deps
go install
unused_deps TARGET...
Here, TARGET is a space-separated list of Bazel labels, with support for :all and ...