diff --git a/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/model/Five.java b/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/model/Five.java
index 9ecbfdd67..e8174f6c5 100644
--- a/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/model/Five.java
+++ b/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/model/Five.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008, 2009, 2011, 2015 XStream Committers.
+ * Copyright (C) 2008, 2009, 2011, 2015, 2022 XStream Committers.
  * All rights reserved.
  *
  * The software in this package is published under the terms of the BSD
@@ -23,9 +23,9 @@ public class Five extends One {
     private int two;
     private boolean three;
     private char four;
-    private StringBuffer five;
+    private CharSequence five;
 
-    public Five(String one, int two, boolean three, char four, StringBuffer five) {
+    public Five(String one, int two, boolean three, char four, CharSequence five) {
         super(one);
         this.two = two;
         this.three = three;
diff --git a/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/model/SerializableFive.java b/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/model/SerializableFive.java
index cefc10d0b..d52e50437 100644
--- a/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/model/SerializableFive.java
+++ b/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/model/SerializableFive.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008, 2009, 2011, 2015 XStream Committers.
+ * Copyright (C) 2008, 2009, 2011, 2015, 2022 XStream Committers.
  * All rights reserved.
  *
  * The software in this package is published under the terms of the BSD
@@ -27,9 +27,9 @@ public class SerializableFive extends SerializableOne {
     private int two;
     private boolean three;
     private char four;
-    private StringBuffer five;
+    private CharSequence five;
 
-    public SerializableFive(String one, int two, boolean three, char four, StringBuffer five) {
+    public SerializableFive(String one, int two, boolean three, char four, CharSequence five) {
         super(one);
         this.two = two;
         this.three = three;
diff --git a/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/targets/JavaBeanTarget.java b/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/targets/JavaBeanTarget.java
index 39a870f26..814506e0a 100644
--- a/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/targets/JavaBeanTarget.java
+++ b/xstream-benchmark/src/java/com/thoughtworks/xstream/tools/benchmark/targets/JavaBeanTarget.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009, 2011, 2015 XStream Committers.
+ * Copyright (C) 2009, 2011, 2015, 2022 XStream Committers.
  * All rights reserved.
  *
  * The software in this package is published under the terms of the BSD
@@ -41,7 +41,7 @@ public JavaBeanTarget() {
         five.setTwo(2);
         five.setThree(true);
         five.setFour('4');
-        five.setFive(new StringBuffer("5"));
+        five.setFive(new StringBuilder("5"));
         list.add(five);
     }