--- old/src/java.xml/share/classes/javax/xml/datatype/XMLGregorianCalendar.java	2020-08-07 18:58:55.469682072 +0000
+++ new/src/java.xml/share/classes/javax/xml/datatype/XMLGregorianCalendar.java	2020-08-07 18:58:55.175674611 +0000
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2003, 2017, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2003, 2020, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -28,6 +28,7 @@
 import javax.xml.namespace.QName;
 import java.math.BigDecimal;
 import java.math.BigInteger;
+import java.util.Arrays;
 import java.util.TimeZone;
 import java.util.GregorianCalendar;
 
@@ -688,10 +689,12 @@
      */
     @Override
     public boolean equals(Object obj) {
-
         if (obj == null || !(obj instanceof XMLGregorianCalendar)) {
             return false;
         }
+        if (obj == this) {
+            return true;
+        }
         return compare((XMLGregorianCalendar) obj) == DatatypeConstants.EQUAL;
     }
 
@@ -716,12 +719,10 @@
         if (timezone != 0) {
             gc = this.normalize();
         }
-        return gc.getYear()
-                + gc.getMonth()
-                + gc.getDay()
-                + gc.getHour()
-                + gc.getMinute()
-                + gc.getSecond();
+
+        int[] elements = {gc.getYear(), gc.getMonth(), gc.getDay(), gc.getHour(),
+                          gc.getMinute(), gc.getSecond(), gc.getMillisecond()};
+        return Arrays.hashCode(elements);
     }
 
     /**