diff --git a/gee-rpc/day3-service/service.go b/gee-rpc/day3-service/service.go
index e0711cd..306683c 100644
--- a/gee-rpc/day3-service/service.go
+++ b/gee-rpc/day3-service/service.go
@@ -8,10 +8,14 @@ import (
 )
 
 type methodType struct {
-	Method    reflect.Method
+	method    reflect.Method
 	ArgType   reflect.Type
 	ReplyType reflect.Type
-	NumCalls  uint64
+	numCalls  uint64
+}
+
+func (m *methodType) NumCalls() uint64 {
+	return atomic.LoadUint64(&m.numCalls)
 }
 
 func (m *methodType) newArgv() reflect.Value {
@@ -72,7 +76,7 @@ func (s *service) registerMethods() {
 			continue
 		}
 		s.method[method.Name] = &methodType{
-			Method:    method,
+			method:    method,
 			ArgType:   argType,
 			ReplyType: replyType,
 		}
@@ -81,8 +85,8 @@ func (s *service) registerMethods() {
 }
 
 func (s *service) call(m *methodType, argv, replyv reflect.Value) error {
-	atomic.AddUint64(&m.NumCalls, 1)
-	f := m.Method.Func
+	atomic.AddUint64(&m.numCalls, 1)
+	f := m.method.Func
 	returnValues := f.Call([]reflect.Value{s.rcvr, argv, replyv})
 	if errInter := returnValues[0].Interface(); errInter != nil {
 		return errInter.(error)
diff --git a/gee-rpc/day3-service/service_test.go b/gee-rpc/day3-service/service_test.go
index 4b35124..c8266df 100644
--- a/gee-rpc/day3-service/service_test.go
+++ b/gee-rpc/day3-service/service_test.go
@@ -15,7 +15,7 @@ func (f Foo) Sum(args Args, reply *int) error {
 	return nil
 }
 
-// it's not a exported method
+// it's not a exported Method
 func (f Foo) sum(args Args, reply *int) error {
 	*reply = args.Num1 + args.Num2
 	return nil
@@ -30,9 +30,9 @@ func _assert(condition bool, msg string, v ...interface{}) {
 func TestNewService(t *testing.T) {
 	var foo Foo
 	s := newService(&foo)
-	_assert(len(s.method) == 1, "wrong service method, expect 1, but got %d", len(s.method))
+	_assert(len(s.method) == 1, "wrong service Method, expect 1, but got %d", len(s.method))
 	mType := s.method["Sum"]
-	_assert(mType != nil, "wrong method, Sum shouldn't nil")
+	_assert(mType != nil, "wrong Method, Sum shouldn't nil")
 }
 
 func TestMethodType_Call(t *testing.T) {
@@ -44,5 +44,5 @@ func TestMethodType_Call(t *testing.T) {
 	replyv := mType.newReplyv()
 	argv.Set(reflect.ValueOf(Args{Num1: 1, Num2: 3}))
 	err := s.call(mType, argv, replyv)
-	_assert(err == nil && *replyv.Interface().(*int) == 4 && mType.numCalls == 1, "failed to call Foo.Sum")
+	_assert(err == nil && *replyv.Interface().(*int) == 4 && mType.NumCalls() == 1, "failed to call Foo.Sum")
 }
diff --git a/gee-rpc/day4-http-debug/service.go b/gee-rpc/day4-http-debug/service.go
index e0711cd..306683c 100644
--- a/gee-rpc/day4-http-debug/service.go
+++ b/gee-rpc/day4-http-debug/service.go
@@ -8,10 +8,14 @@ import (
 )
 
 type methodType struct {
-	Method    reflect.Method
+	method    reflect.Method
 	ArgType   reflect.Type
 	ReplyType reflect.Type
-	NumCalls  uint64
+	numCalls  uint64
+}
+
+func (m *methodType) NumCalls() uint64 {
+	return atomic.LoadUint64(&m.numCalls)
 }
 
 func (m *methodType) newArgv() reflect.Value {
@@ -72,7 +76,7 @@ func (s *service) registerMethods() {
 			continue
 		}
 		s.method[method.Name] = &methodType{
-			Method:    method,
+			method:    method,
 			ArgType:   argType,
 			ReplyType: replyType,
 		}
@@ -81,8 +85,8 @@ func (s *service) registerMethods() {
 }
 
 func (s *service) call(m *methodType, argv, replyv reflect.Value) error {
-	atomic.AddUint64(&m.NumCalls, 1)
-	f := m.Method.Func
+	atomic.AddUint64(&m.numCalls, 1)
+	f := m.method.Func
 	returnValues := f.Call([]reflect.Value{s.rcvr, argv, replyv})
 	if errInter := returnValues[0].Interface(); errInter != nil {
 		return errInter.(error)
diff --git a/gee-rpc/day4-http-debug/service_test.go b/gee-rpc/day4-http-debug/service_test.go
index 7ba2786..c8266df 100644
--- a/gee-rpc/day4-http-debug/service_test.go
+++ b/gee-rpc/day4-http-debug/service_test.go
@@ -44,5 +44,5 @@ func TestMethodType_Call(t *testing.T) {
 	replyv := mType.newReplyv()
 	argv.Set(reflect.ValueOf(Args{Num1: 1, Num2: 3}))
 	err := s.call(mType, argv, replyv)
-	_assert(err == nil && *replyv.Interface().(*int) == 4 && mType.NumCalls == 1, "failed to call Foo.Sum")
+	_assert(err == nil && *replyv.Interface().(*int) == 4 && mType.NumCalls() == 1, "failed to call Foo.Sum")
 }