diff --git a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/JSON.mustache b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/JSON.mustache
index d6883b98231f..6cf7ec7898c4 100644
--- a/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/JSON.mustache
+++ b/modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson/JSON.mustache
@@ -109,7 +109,7 @@ public class JSON {
         return clazz;
     }
 
-    {
+    static {
         GsonBuilder gsonBuilder = createGson();
         gsonBuilder.registerTypeAdapter(Date.class, dateTypeAdapter);
         gsonBuilder.registerTypeAdapter(java.sql.Date.class, sqlDateTypeAdapter);