diff --git a/springfox-spring-web/src/main/java/springfox/documentation/spring/web/plugins/DefaultRequestHandlerCombiner.java b/springfox-spring-web/src/main/java/springfox/documentation/spring/web/plugins/DefaultRequestHandlerCombiner.java
index <HASH>..<HASH> 100644
--- a/springfox-spring-web/src/main/java/springfox/documentation/spring/web/plugins/DefaultRequestHandlerCombiner.java
+++ b/springfox-spring-web/src/main/java/springfox/documentation/spring/web/plugins/DefaultRequestHandlerCombiner.java
@@ -110,7 +110,7 @@ class DefaultRequestHandlerCombiner implements RequestHandlerCombiner {
   }
 
   private String keys(List<RequestHandler> source) {
-    final StringBuffer sb = new StringBuffer("Request Handlers with duplicate keys {");
+    final StringBuilder sb = new StringBuilder("Request Handlers with duplicate keys {");
     for (int i = 0; i < source.size(); i++) {
       sb.append('\t')
           .append(i)
Replaced StringBuffer with StringBuilder

(<I>)

(cherry picked from commit ebeb<I>da<I>d<I>ee0e<I>cad<I>fc2e<I>ce<I>e)