fix a typo
diff --git a/examples/helloworld/greeter_server/main.go b/examples/helloworld/greeter_server/main.go
index ba985df..66010a5 100644
--- a/examples/helloworld/greeter_server/main.go
+++ b/examples/helloworld/greeter_server/main.go
@@ -46,7 +46,7 @@
 	port = ":50051"
 )
 
-// server is used to implement hellowrld.GreeterServer.
+// server is used to implement helloworld.GreeterServer.
 type server struct{}
 
 // SayHello implements helloworld.GreeterServer