diff --git a/japicmp/src/main/java/japicmp/cmp/JApiCmpArchive.java b/japicmp/src/main/java/japicmp/cmp/JApiCmpArchive.java
index 91c4df65..55e8f88c 100644
--- a/japicmp/src/main/java/japicmp/cmp/JApiCmpArchive.java
+++ b/japicmp/src/main/java/japicmp/cmp/JApiCmpArchive.java
@@ -39,7 +39,7 @@ public String getName() {
 
 	@Override
 	public String toString() {
-		final StringBuffer sb = new StringBuffer("JApiCmpArchive{");
+		StringBuilder sb = new StringBuilder("JApiCmpArchive{");
 		sb.append("file=").append(file);
 		sb.append(", bytes=");
 		if (bytes == null) sb.append("null");