diff --git a/src/main/java/de/siegmar/logbackgelf/GelfMessage.java b/src/main/java/de/siegmar/logbackgelf/GelfMessage.java
index 2c39f75..b13a6c5 100644
--- a/src/main/java/de/siegmar/logbackgelf/GelfMessage.java
+++ b/src/main/java/de/siegmar/logbackgelf/GelfMessage.java
@@ -91,9 +91,8 @@ public StringBuilder toJSON() {
                 .appendToJSONUnquoted("timestamp", timestampToGelfNotation(timestamp))
                 .appendToJSONUnquoted("level", level);
 
-            for (final Map.Entry<String, Object> entry : additionalFields.entrySet()) {
-                jsonEncoder.appendToJSON('_' + entry.getKey(), entry.getValue());
-            }
+            additionalFields
+                .forEach((key, value) -> jsonEncoder.appendToJSON('_' + key, value));
         }
 
         return sb;
diff --git a/src/test/java/de/siegmar/logbackgelf/custom/CustomGelfEncoder.java b/src/test/java/de/siegmar/logbackgelf/custom/CustomGelfEncoder.java
index c174b79..1897b1e 100644
--- a/src/test/java/de/siegmar/logbackgelf/custom/CustomGelfEncoder.java
+++ b/src/test/java/de/siegmar/logbackgelf/custom/CustomGelfEncoder.java
@@ -19,11 +19,7 @@
 
 package de.siegmar.logbackgelf.custom;
 
-import java.io.IOException;
-import java.io.OutputStream;
-import java.io.UncheckedIOException;
 import java.nio.charset.StandardCharsets;
-import java.security.DigestOutputStream;
 import java.security.MessageDigest;
 import java.util.Map;
 
@@ -49,14 +45,7 @@ protected GelfMessage buildGelfMessage(final long timestamp, final int logLevel,
 
     private static String buildHash(final GelfMessage gelfMessage) {
         final MessageDigest digest = new SHA256.Digest();
-
-        try (DigestOutputStream dos = new DigestOutputStream(OutputStream.nullOutputStream(), digest)) {
-            dos.write(gelfMessage.toJSON().toString().getBytes(StandardCharsets.UTF_8));
-        } catch (final IOException e) {
-            throw new UncheckedIOException(e);
-        }
-
-        return toHex(digest.digest());
+        return toHex(digest.digest(gelfMessage.toJSON().toString().getBytes(StandardCharsets.UTF_8)));
     }
 
     private static String toHex(final byte[] data) {