File reproducible-javadoc-timestamp.patch of Package java-17-openjdk.30331

--- a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/HtmlConfiguration.java
+++ b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/HtmlConfiguration.java
@@ -213,6 +213,12 @@ public class HtmlConfiguration extends BaseConfiguration {
         }
         docletVersion = v;
 
+        if (System.getenv("SOURCE_DATE_EPOCH") != null) {
+            startTime = new Date(1000 * Long.parseLong(System.getenv("SOURCE_DATE_EPOCH")));
+        } else {
+            startTime = new Date();
+        }
+
         conditionalPages = EnumSet.noneOf(ConditionalPage.class);
     }
     protected void initConfiguration(DocletEnvironment docEnv,
@@ -223,7 +229,7 @@ public class HtmlConfiguration extends BaseConfiguration {
     }
 
     private final Runtime.Version docletVersion;
-    public final Date startTime = new Date();
+    public final Date startTime;
 
     @Override
     public Runtime.Version getDocletVersion() {
--- a/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/Head.java
+++ b/src/jdk.javadoc/share/classes/jdk/javadoc/internal/doclets/formats/html/markup/Head.java
@@ -33,6 +33,7 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.Date;
 import java.util.List;
+import java.util.TimeZone;
 
 import jdk.javadoc.internal.doclets.toolkit.Content;
 import jdk.javadoc.internal.doclets.toolkit.util.DocPath;
@@ -265,6 +266,9 @@ public class Head extends Content {
 
         if (showTimestamp) {
             SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
+            if (System.getenv("SOURCE_DATE_EPOCH") != null) {
+                dateFormat.setTimeZone(TimeZone.getTimeZone("UTC"));
+            }
             tree.add(HtmlTree.META("dc.created", dateFormat.format(generatedDate)));
         }
 
@@ -298,7 +302,14 @@ public class Head extends Content {
         String text = "Generated by javadoc"; // marker string, deliberately not localized
         text += " (" + docletVersion.feature() + ")";
         if (timestamp) {
-            text += " on " + now;
+            text += " on ";
+            if (System.getenv("SOURCE_DATE_EPOCH") == null) {
+                text += now;
+            } else {
+                SimpleDateFormat fmt = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss z");
+                fmt.setTimeZone(TimeZone.getTimeZone("UTC"));
+                text += fmt.format(now);
+            }
         }
         return new Comment(text);
     }