Move from MailDateFormat (not thread safe) to DateTimeFormatter #590

api/src/main/java/jakarta/mail/internet/MimeMessage.java

@@ -40,10 +40,14 @@
 import java.io.OutputStream;
 import java.io.UnsupportedEncodingException;
 import java.text.ParseException;
+import java.time.Instant;
+import java.time.ZoneOffset;
+import java.time.format.DateTimeFormatter;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.Enumeration;
 import java.util.List;
+import java.util.Locale;
 import java.util.Properties;
 import java.util.ServiceConfigurationError;
 
@@ -173,7 +177,10 @@ public class MimeMessage extends Message implements MimePart {
     protected Object cachedContent;
 
     // Used to parse dates
-    private static final MailDateFormat mailDateFormat = new MailDateFormat();
+    static final DateTimeFormatter mailDateFormat = DateTimeFormatter
+            .ofPattern("EEE, d MMM yyyy HH:mm:ss Z (z)")
+            .withLocale(Locale.US)
+            .withZone(ZoneOffset.systemDefault());
 
     // Should addresses in headers be parsed in "strict" mode?
     private boolean strict = true;
@@ -546,10 +553,10 @@ protected Object readResolve() throws ObjectStreamException {
      * between the type and the corresponding RFC 822 header is
      * as follows:
      * <pre>
-     * 		Message.RecipientType.TO		"To"
-     * 		Message.RecipientType.CC		"Cc"
-     * 		Message.RecipientType.BCC		"Bcc"
-     * 		MimeMessage.RecipientType.NEWSGROUPS	"Newsgroups"
+     *          Message.RecipientType.TO                "To"
+     *          Message.RecipientType.CC                "Cc"
+     *          Message.RecipientType.BCC               "Bcc"
+     *          MimeMessage.RecipientType.NEWSGROUPS    "Newsgroups"
      * </pre><br>
      *
      * Returns null if the header specified by the type is not found
@@ -902,10 +909,8 @@ public Date getSentDate() throws MessagingException {
         String s = getHeader("Date", null);
         if (s != null) {
             try {
-                synchronized (mailDateFormat) {
-                    return mailDateFormat.parse(s);
-                }
-            } catch (ParseException pex) {
+                return Date.from(Instant.from(mailDateFormat.parse(s)));
+            } catch (RuntimeException e) {
                 return null;
             }
         }
@@ -930,9 +935,7 @@ public void setSentDate(Date d) throws MessagingException {
         if (d == null)
             removeHeader("Date");
         else {
-            synchronized (mailDateFormat) {
-                setHeader("Date", mailDateFormat.format(d));
-            }
+            setHeader("Date", mailDateFormat.format(d.toInstant()));
         }
     }
 
@@ -1455,10 +1458,10 @@ public InputStream getRawInputStream() throws MessagingException {
      *  class MimePartDataSource implements DataSource {
      *      public getInputStream() {
      *          return MimeUtility.decode(
-     * 		     getContentStream(), getEncoding());
+     *               getContentStream(), getEncoding());
      *      }
      *
-     * 		.... &lt;other DataSource methods&gt;
+     *          .... &lt;other DataSource methods&gt;
      *  }
      * </pre></blockquote>
      *

api/src/test/java/jakarta/mail/internet/MimeMessageTest.java

@@ -0,0 +1,42 @@
+/*
+ * Copyright (c) 2024 Oracle and/or its affiliates. All rights reserved.
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Eclipse Public License v. 2.0, which is available at
+ * http://www.eclipse.org/legal/epl-2.0.
+ *
+ * This Source Code may also be made available under the following Secondary
+ * Licenses when the conditions for such availability set forth in the
+ * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
+ * version 2 with the GNU Classpath Exception, which is available at
+ * https://www.gnu.org/software/classpath/license.html.
+ *
+ * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
+ */
+
+package jakarta.mail.internet;
+
+import static org.junit.Assert.assertEquals;
+
+import java.text.ParseException;
+import java.time.Instant;
+import java.time.format.DateTimeFormatter;
+import java.util.Date;
+
+import org.junit.Test;
+
+public class MimeMessageTest {
+
+    @Test
+    public void dateTimeFormatter() throws ParseException {
+        MailDateFormat mailDateFormat1 = new MailDateFormat();
+        DateTimeFormatter mailDateFormat2 = MimeMessage.mailDateFormat;
+        Date date = new Date(1341100798000L);
+        String s1 = mailDateFormat1.format(date);
+        String s2 = mailDateFormat2.format(date.toInstant());
+        assertEquals(s1, s2);
+        Date d1 = mailDateFormat1.parse(s1);
+        Date d2 = Date.from(Instant.from(mailDateFormat2.parse(s1)));
+        assertEquals(d1, d2);
+    }
+}