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

Signed-off-by: Jorge Bescos Gascon <[email protected]>

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2021 Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 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
@@ -25,10 +25,14 @@
 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 jakarta.activation.DataHandler;
@@ -172,7 +176,10 @@ 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;
@@ -895,10 +902,8 @@ 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 pex) {
 		return null;
 	    }
 	}
@@ -923,9 +928,7 @@ 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()));
 	}
     }
 

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);
+    }
+}