diff --git a/org.eclipse.jgit.lfs.server/src/org/eclipse/jgit/lfs/server/s3/SignerV4.java b/org.eclipse.jgit.lfs.server/src/org/eclipse/jgit/lfs/server/s3/SignerV4.java
index 08bb4b96f..f95b605c8 100644
--- a/org.eclipse.jgit.lfs.server/src/org/eclipse/jgit/lfs/server/s3/SignerV4.java
+++ b/org.eclipse.jgit.lfs.server/src/org/eclipse/jgit/lfs/server/s3/SignerV4.java
@@ -229,12 +229,12 @@ private static String formatAuthorizationHeader(
 
 	private static void addHostHeader(URL url,
 			Map<String, String> headers) {
-		String hostHeader = url.getHost();
+		StringBuilder hostHeader = new StringBuilder(url.getHost());
 		int port = url.getPort();
 		if (port > -1) {
-			hostHeader.concat(":" + Integer.toString(port)); //$NON-NLS-1$
+			hostHeader.append(":").append(port); //$NON-NLS-1$
 		}
-		headers.put("Host", hostHeader); //$NON-NLS-1$
+		headers.put("Host", hostHeader.toString()); //$NON-NLS-1$
 	}
 
 	private static String canonicalizeHeaderNames(