diff --git a/service/cache/cache.go b/service/cache/cache.go
index 7ed7ffc..b061887 100644
--- a/service/cache/cache.go
+++ b/service/cache/cache.go
@@ -8,7 +8,7 @@ import (
 
 type LruCache struct {
 	*lru.Cache
-	mutex sync.Mutex
+	sync.Mutex
 }
 
 func NewLruCache(maxEntries int) *LruCache {
@@ -18,14 +18,14 @@ func NewLruCache(maxEntries int) *LruCache {
 }
 
 func (l *LruCache) Add(key lru.Key, value interface{}) {
-	l.mutex.Lock()
+	l.Lock()
 	l.Cache.Add(key, value)
-	l.mutex.Unlock()
+	l.Unlock()
 }
 func (l *LruCache) Get(key lru.Key) (value interface{}, ok bool) {
-	l.mutex.Lock()
+	l.Lock()
 	value, ok = l.Cache.Get(key)
-	l.mutex.Unlock()
+	l.Unlock()
 	return
 }
 
diff --git a/service/cache/cache_test.go b/service/cache/cache_test.go
index 012e5e9..dc80fb5 100644
--- a/service/cache/cache_test.go
+++ b/service/cache/cache_test.go
@@ -9,7 +9,7 @@ func TestLruCache_Add(t *testing.T) {
 	t.Logf("1: %+v %+v", v, ok)
 	lruCache.Add(11, 10)
 	lruCache.Add(13, 10)
-	lruCache.Add(14, 10)
 	v, ok = lruCache.Get(10)
 	t.Logf("2: %+v %+v", v, ok)
+	lruCache.Add(14, 10)
 }