diff --git a/src/main/native/jniTestNative.c b/src/main/native/jniTestNative.c
index 12368dc..b09c371 100644
--- a/src/main/native/jniTestNative.c
+++ b/src/main/native/jniTestNative.c
@@ -11,15 +11,17 @@ extern "C" {
 JNIEXPORT void JNICALL Java_com_zeekling_cn_jni_JniTest_say(JNIEnv* env, jclass cls,  jstring j_str) {
     const char *c_str = NULL;
     char buff[128] = { 0 };
-    c_str = (*env)->GetStringUTFChars(env, j_str, NULL);
+    jboolean isCopy;
+    c_str = (*env)->GetStringUTFChars(env, j_str, &isCopy);
     if (c_str == NULL)
     {
         printf("out of memory.\n");
         return NULL;
     }
-    (*env)->ReleaseStringUTFChars(env, j_str, c_str);
+
     printf("Hello,I'm C++,the Java Str is:%s\n", c_str);
     sprintf(buff, "hello %s", c_str);
+    (*env)->ReleaseStringUTFChars(env, j_str, c_str);
     return (*env)->NewStringUTF(env, buff);
 }
 #ifdef __cplusplus