Add @deprecated javadoc to JapaneseCalendar.CURRENT_ERA

@Deprecated annotation is not enough. Both annotation and javadoc
are needed for a deprecated Android API.

Change-Id: I6a7c380a3ddfffb397b295fd5b874385ec1a0b85
Fix: 77850660
Test: @deprecated javadoc is added after running the code gen script
diff --git a/android_icu4j/src/main/java/android/icu/util/JapaneseCalendar.java b/android_icu4j/src/main/java/android/icu/util/JapaneseCalendar.java
index 504117a..f7f8b83 100644
--- a/android_icu4j/src/main/java/android/icu/util/JapaneseCalendar.java
+++ b/android_icu4j/src/main/java/android/icu/util/JapaneseCalendar.java
@@ -335,6 +335,7 @@
 
     // Constant for the current era.  This must be regularly updated.
     /**
+     * @deprecated on Android but not deprecated in ICU
      */
     @Deprecated
     static public final int CURRENT_ERA;
diff --git a/tools/srcgen/src/main/java/com/android/icu4j/srcgen/Icu4jTransform.java b/tools/srcgen/src/main/java/com/android/icu4j/srcgen/Icu4jTransform.java
index d5b76d0..9dfc451 100644
--- a/tools/srcgen/src/main/java/com/android/icu4j/srcgen/Icu4jTransform.java
+++ b/tools/srcgen/src/main/java/com/android/icu4j/srcgen/Icu4jTransform.java
@@ -888,8 +888,10 @@
           // Usually used for avoiding the new API introduced by upstream to show up in Android.
           createHideNonWhitelistedRule(whitelistedApiPath),
 
-          // AST change: Add @Deprecated annotation to deprecated API in Android
-          createMarkDeprecatedClassesRule(),
+          // AST change: Add @Deprecated annotation and @deprecated doc to deprecated API in Android
+          createMarkElementsWithDeprecatedAnnotationRule(),
+          createMarkElementsWithDeprecatedJavadocTagRule(),
+
 
           // AST change: Remove JavaDoc tags that Android has no need of:
           // @hide has been added in place of @draft, @provisional and @internal
@@ -936,13 +938,20 @@
           new TagMatchingDeclarations(blacklist, "@hide original deprecated declaration"));
     }
 
-    private static Rule createMarkDeprecatedClassesRule() {
+    private static Rule createMarkElementsWithDeprecatedAnnotationRule() {
       List<BodyDeclarationLocator> locators =
           BodyDeclarationLocators.createLocatorsFromStrings(ANDROID_DEPRECATED_SET);
       return createOptionalRule(AddAnnotation.markerAnnotationFromLocators(
           "Deprecated", locators));
     }
 
+    private static Rule createMarkElementsWithDeprecatedJavadocTagRule() {
+      List<BodyDeclarationLocator> locators =
+          BodyDeclarationLocators.createLocatorsFromStrings(ANDROID_DEPRECATED_SET);
+      return createOptionalRule(new TagMatchingDeclarations(locators,
+          "@deprecated on Android but not deprecated in ICU"));
+    }
+
     private static Rule createHideBlacklistedDeclarationsRule() {
       List<BodyDeclarationLocator> blacklist =
           BodyDeclarationLocators.createLocatorsFromStrings(DECLARATIONS_TO_HIDE);