question: private void extractProtoSources ( Set < String > extracted , String protoFile ) { if ( ! extracted . add ( protoFile ) ) { return ; } String content = copyTestData ( protoFile ) ; Matcher matcher = PROTO_IMPORT_PATTERN . matcher ( content ) ; while ( matcher . find ( ) ) { extractProtoSources ( extracted , matcher . group ( 1 ) ) ; } }
target:  Collect all needed proto files as resources from the classpath and store them in the temporary directory, so protoc can find them.