--- maven-javadoc-plugin-3.3.2/src/main/java/org/apache/maven/plugins/javadoc/AbstractJavadocMojo.java	2022-02-07 20:52:42.000000000 +0100
+++ maven-javadoc-plugin-3.3.2/src/main/java/org/apache/maven/plugins/javadoc/AbstractJavadocMojo.java	2022-03-14 07:21:32.537764730 +0100
@@ -5969,7 +5969,7 @@
             if ( !isUpToDate( cmd ) )
             {
                 doExecuteJavadocCommandLine( cmd, javadocOutputDirectory );
-                StaleHelper.writeStaleData( cmd, staleDataPath.toPath() );
+                StaleHelper.writeStaleData( cmd, staleDataPath.toPath(), Charset.forName(getEncoding()) );
             }
         }
         else
--- maven-javadoc-plugin-3.3.2/src/main/java/org/apache/maven/plugins/javadoc/StaleHelper.java	2022-02-07 20:52:42.000000000 +0100
+++ maven-javadoc-plugin-3.3.2/src/main/java/org/apache/maven/plugins/javadoc/StaleHelper.java	2022-03-14 07:19:21.228985255 +0100
@@ -134,16 +134,17 @@
      *
      * @param cmd the command line
      * @param path the stale data path
+	 * @param encoding the encoding of source files
      * @throws MavenReportException if an error occurs
      */
-    public static void writeStaleData( Commandline cmd, Path path )
+    public static void writeStaleData( Commandline cmd, Path path, Charset charset )
             throws MavenReportException
     {
         try
         {
             String curdata = getStaleData( cmd );
             Files.createDirectories( path.getParent() );
-            Files.write( path, Collections.singleton( curdata ), Charset.defaultCharset() );
+            Files.write( path, Collections.singleton( curdata ), charset );
         }
         catch ( IOException e )
         {
@@ -151,6 +152,19 @@
         }
     }
 
+    /**
+     * Write the data used to detect a stale javadoc
+     *
+     * @param cmd the command line
+     * @param path the stale data path
+     * @throws MavenReportException if an error occurs
+     */
+    public static void writeStaleData( Commandline cmd, Path path )
+            throws MavenReportException
+    {
+        writeStaleData( cmd, path, Charset.defaultCharset());
+    }
+
     private static Collection<Path> walk( Path dir )
     {
         Collection<Path> paths = new ArrayList<>();