Multipart performs blocking call in every instantiation #699

api/src/main/java/jakarta/mail/BodyPart.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 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
@@ -39,13 +39,6 @@ public abstract class BodyPart implements Part {
      */
     protected Multipart parent;
 
-    /**
-     * Instance of stream provider.
-     *
-     * @since JavaMail 2.1
-     */
-    protected final StreamProvider streamProvider = StreamProvider.provider();
-
     /**
      * Creates a default {@code BodyPart}.
      */
@@ -74,4 +67,14 @@ public Multipart getParent() {
     void setParent(Multipart parent) {
         this.parent = parent;
     }
+
+    @Override
+    public StreamProvider getStreamProvider() throws MessagingException {
+        if (parent != null) {
+            return parent.getStreamProvider();
+        } else {
+            return Part.super.getStreamProvider();
+        }
+    }
+
 }

api/src/main/java/jakarta/mail/Message.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 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
@@ -17,11 +17,13 @@
 package jakarta.mail;
 
 import jakarta.mail.search.SearchTerm;
+import jakarta.mail.util.StreamProvider;
 
 import java.io.InvalidObjectException;
 import java.io.ObjectStreamException;
 import java.io.Serializable;
 import java.util.Date;
+import java.util.ServiceConfigurationError;
 
 /**
  * This class models an email message. This is an abstract class.
@@ -705,4 +707,22 @@ protected void setExpunged(boolean expunged) {
     public boolean match(SearchTerm term) throws MessagingException {
         return term.match(this);
     }
+
+    @Override
+    public StreamProvider getStreamProvider() throws MessagingException {
+        try {
+            try {
+                final Session s = this.session;
+                if (s != null) {
+                    return s.getStreamProvider();
+                } else {
+                    return Session.getDefaultInstance(System.getProperties(), null).getStreamProvider();
+                }
+            } catch (ServiceConfigurationError sce) {
+                throw new IllegalStateException(sce);
+            }
+        } catch (RuntimeException re) {
+            throw new MessagingException("Unable to get " + StreamProvider.class.getName(), re);
+        }
+    }
 }

api/src/main/java/jakarta/mail/Multipart.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 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
@@ -61,13 +61,6 @@ public abstract class Multipart {
      */
     protected Part parent;
 
-    /**
-     * Instance of stream provider.
-     *
-     * @since JavaMail 2.1
-     */
-    protected final StreamProvider streamProvider = StreamProvider.provider();
-
     /**
      * Default constructor. An empty Multipart object is created.
      */
@@ -266,4 +259,24 @@ public synchronized Part getParent() {
     public synchronized void setParent(Part parent) {
         this.parent = parent;
     }
+
+    /**
+     * Obtains the {@link StreamProvider} from the parent, if possible.
+     * Otherwise it obtains it from
+     * {@link Session#getDefaultInstance(java.util.Properties, Authenticator)}.
+     *
+     * @return the StreamProvider implementation from the session.
+     * @throws MessagingException if errors.
+     *
+     * @since JavaMail 2.2
+     */
+    protected StreamProvider getStreamProvider() throws MessagingException {
+        Part parent = this.parent;
+        if (parent != null) {
+            return parent.getStreamProvider();
+        } else {
+            return Session.getDefaultInstance(System.getProperties(), null).getStreamProvider();
+        }
+    }
+
 }

api/src/main/java/jakarta/mail/Part.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 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
@@ -17,6 +17,7 @@
 package jakarta.mail;
 
 import jakarta.activation.DataHandler;
+import jakarta.mail.util.StreamProvider;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -453,4 +454,17 @@ Enumeration<Header> getMatchingHeaders(String[] header_names)
      */
     Enumeration<Header> getNonMatchingHeaders(String[] header_names)
             throws MessagingException;
+
+    /**
+     * Obtains the {@link StreamProvider}.
+     * It defaults to {@link Session#getDefaultInstance(java.util.Properties, Authenticator)}.
+     *
+     * @return the StreamProvider.
+     * @throws MessagingException if errors.
+     *
+     * @since JavaMail 2.2
+     */
+    default StreamProvider getStreamProvider() throws MessagingException {
+        return Session.getDefaultInstance(System.getProperties(), null).getStreamProvider();
+    }
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 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
@@ -30,7 +30,6 @@
 import jakarta.mail.Multipart;
 import jakarta.mail.Part;
 import jakarta.mail.util.LineOutputStream;
-import jakarta.mail.util.StreamProvider;
 import jakarta.mail.util.StreamProvider.EncoderTypes;
 
 import java.io.BufferedInputStream;
@@ -1641,7 +1640,7 @@ static void writeTo(MimePart part, OutputStream os, String[] ignoreList)
         } else {
             Map<String, Object> params = new HashMap<>();
             params.put("allowutf8", allowutf8);
-            los = StreamProvider.provider().outputLineStream(os, allowutf8);
+            los = part.getStreamProvider().outputLineStream(os, allowutf8);
         }
 
         // First, write out the header

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

@@ -29,7 +29,6 @@
 import jakarta.mail.Multipart;
 import jakarta.mail.Session;
 import jakarta.mail.util.LineOutputStream;
-import jakarta.mail.util.StreamProvider;
 
 import java.io.BufferedInputStream;
 import java.io.ByteArrayInputStream;
@@ -45,8 +44,6 @@
 import java.util.Enumeration;
 import java.util.List;
 import java.util.Properties;
-import java.util.ServiceConfigurationError;
-
 
 /**
  * This class represents a MIME style email message. It implements
@@ -245,7 +242,7 @@ public MimeMessage(MimeMessage source) throws MessagingException {
             strict = source.strict;
             source.writeTo(bos);
             bos.close();
-            try (InputStream bis = provider().inputSharedByteArray(bos.toByteArray())) {
+            try (InputStream bis = getStreamProvider().inputSharedByteArray(bos.toByteArray())) {
                 parse(bis);
             }
             saved = true;
@@ -1410,7 +1407,7 @@ protected InputStream getContentStream() throws MessagingException {
         if (contentStream != null)
             return ((SharedInputStream) contentStream).newStream(0, -1);
         if (content != null) {
-            return provider().inputSharedByteArray(content);
+            return getStreamProvider().inputSharedByteArray(content);
         }
         throw new MessagingException("No MimeMessage content");
     }
@@ -1917,7 +1914,7 @@ public void writeTo(OutputStream os, String[] ignoreList)
         // Else, the content is untouched, so we can just output it
         // First, write out the header
         Enumeration<String> hdrLines = getNonMatchingHeaderLines(ignoreList);
-        LineOutputStream los = provider().outputLineStream(os, allowutf8);
+        LineOutputStream los = getStreamProvider().outputLineStream(os, allowutf8);
         while (hdrLines.hasMoreElements())
             los.writeln(hdrLines.nextElement());
 
@@ -2322,23 +2319,4 @@ protected MimeMessage createMimeMessage(Session session)
             throws MessagingException {
         return new MimeMessage(session);
     }
-
-    private StreamProvider provider() throws MessagingException {
-        try {
-            try {
-                final Session s = this.session;
-                if (s != null) {
-                    return s.getStreamProvider();
-                } else {
-                    return Session.getDefaultInstance(System.getProperties(),
-                        null).getStreamProvider();
-                }
-            } catch (ServiceConfigurationError sce) {
-                throw new IllegalStateException(sce);
-            }
-        } catch (RuntimeException re) {
-            throw new MessagingException("Unable to get "
-                    + StreamProvider.class.getName(), re);
-        }
-    }
 }

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 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
@@ -520,7 +520,7 @@ public synchronized void writeTo(OutputStream os)
 
         String boundary = "--" +
                 (new ContentType(contentType)).getParameter("boundary");
-        LineOutputStream los = streamProvider.outputLineStream(os, false);
+        LineOutputStream los = getStreamProvider().outputLineStream(os, false);
         // if there's a preamble, write it out
         if (preamble != null) {
             byte[] pb = MimeUtility.getBytes(preamble);
@@ -601,7 +601,7 @@ protected synchronized void parse() throws MessagingException {
 
         try {
             // Skip and save the preamble
-            LineInputStream lin = streamProvider.inputLineStream(in, false);
+            LineInputStream lin = getStreamProvider().inputLineStream(in, false);
             StringBuilder preamblesb = null;
             String line;
             while ((line = lin.readLine()) != null) {

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

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023 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
@@ -78,7 +78,7 @@ public void writeTo(OutputStream os)
         if (os instanceof LineOutputStream) {
             los = (LineOutputStream) os;
         } else {
-            los = streamProvider.outputLineStream(os, false);
+            los = getStreamProvider().outputLineStream(os, false);
         }
 
         // First, write out the header