Module jakarta.mail

Package jakarta.mail.internet

Classes specific to Internet mail systems. This package supports features that are specific to Internet mail systems based on the MIME standard (RFC 2045, RFC 2046, and RFC 2047). The IMAP, SMTP, and POP3 protocols use MimeMessages. Properties

The Jakarta Mail API supports the following standard properties, which may be set in the Session object, or in the Properties object used to create the Session object. The MimeMessage falls back to System properties when created without a Session object. The properties are always set as strings; the Type column describes how the string is interpreted. For example, use 

 session.setProperty("mail.mime.address.strict", "false");

to set the mail.mime.address.strict property, which is of type boolean.

Jakarta Mail properties
Name Type Description
mail.mime.address.strict boolean The mail.mime.address.strict property controls the parsing of address headers. By default, strict parsing of address headers is done. If this property is set to "false", strict parsing is not done and many illegal addresses that sometimes occur in real messages are allowed. See the InternetAddress class for details.
mail.mime.allowutf8 boolean If set to "true", UTF-8 strings are allowed in message headers, e.g., in addresses. This should only be set if the mail server also supports UTF-8.

The Jakarta Mail API specification requires support for the following properties, which must be set in the System properties. The properties are always set as strings; the Type column describes how the string is interpreted. For example, use 

 System.setProperty("mail.mime.decodetext.strict", "false");

to set the mail.mime.decodetext.strict property, which is of type boolean.

Jakarta Mail System properties
Name Type Description
mail.mime.charset String The mail.mime.charset System property can be used to specify the default MIME charset to use for encoded words and text parts that don't otherwise specify a charset. Normally, the default MIME charset is derived from the default Java charset, as specified in the file.encoding System property. Most applications will have no need to explicitly set the default MIME charset. In cases where the default MIME charset to be used for mail messages is different than the charset used for files stored on the system, this property should be set.
mail.mime.decodetext.strict boolean The mail.mime.decodetext.strict property controls decoding of MIME encoded words. The MIME spec requires that encoded words start at the beginning of a whitespace separated word. Some mailers incorrectly include encoded words in the middle of a word. If the mail.mime.decodetext.strict System property is set to "false", an attempt will be made to decode these illegal encoded words. The default is true.
mail.mime.encodeeol.strict boolean The mail.mime.encodeeol.strict property controls the choice of Content-Transfer-Encoding for MIME parts that are not of type "text". Often such parts will contain textual data for which an encoding that allows normal end of line conventions is appropriate. In rare cases, such a part will appear to contain entirely textual data, but will require an encoding that preserves CR and LF characters without change. If the mail.mime.encodeeol.strict System property is set to "true", such an encoding will be used when necessary. The default is false.
mail.mime.decodefilename boolean If set to "true", the getFileName method uses the MimeUtility method decodeText to decode any non-ASCII characters in the filename. Note that this decoding violates the MIME specification, but is useful for interoperating with some mail clients that use this convention. The default is false.
mail.mime.encodefilename boolean If set to "true", the setFileName method uses the MimeUtility method encodeText to encode any non-ASCII characters in the filename. Note that this encoding violates the MIME specification, but is useful for interoperating with some mail clients that use this convention. The default is false.
mail.mime.decodeparameters boolean If set to "false", non-ASCII parameters in a ParameterList, e.g., in a Content-Type header, will not be decoded as specified by RFC 2231. The default is true.
mail.mime.encodeparameters boolean If set to "false", non-ASCII parameters in a ParameterList, e.g., in a Content-Type header, will not be encoded as specified by RFC 2231. The default is true.
mail.mime.multipart. ignoremissingendboundary boolean Normally, when parsing a multipart MIME message, a message that is missing the final end boundary line is not considered an error. The data simply ends at the end of the input. Note that messages of this form violate the MIME specification. If the property mail.mime.multipart.ignoremissingendboundary is set to false, such messages are considered an error and a MesagingException will be thrown when parsing such a message.
mail.mime.multipart. ignoremissingboundaryparameter boolean If the Content-Type header for a multipart content does not have a boundary parameter, the multipart parsing code will look for the first line in the content that looks like a boundary line and extract the boundary parameter from the line. If this property is set to "false", a MessagingException will be thrown if the Content-Type header doesn't specify a boundary parameter. The default is true.
mail.mime.multipart. ignoreexistingboundaryparameter boolean Normally the boundary parameter in the Content-Type header of a multipart body part is used to specify the separator between parts of the multipart body. This System property may be set to "true" to cause the parser to look for a line in the multipart body that looks like a boundary line and use that value as the separator between subsequent parts. This may be useful in cases where a broken anti-virus product has rewritten the message incorrectly such that the boundary parameter and the actual boundary value no longer match. The default value of this property is false.
mail.mime.multipart. allowempty boolean Normally, when writing out a MimeMultipart that contains no body parts, or when trying to parse a multipart message with no body parts, a MessagingException is thrown. The MIME spec does not allow multipart content with no body parts. This System property may be set to "true" to override this behavior. When writing out such a MimeMultipart, a single empty part will be included. When reading such a multipart, a MimeMultipart will be created with no body parts. The default value of this property is false.

The following properties are supported by the EE4J implementation of Jakarta Mail, but are not currently a required part of the specification. These must be set as Session properties. The names, types, defaults, and semantics of these properties may change in future releases.

Jakarta Mail implementation properties
Name Type Description
mail.alternates String A string containing other email addresses that the current user is known by. The MimeMessage reply method will eliminate any of these addresses from the recipient list in the message it constructs, to avoid sending the reply back to the sender.
mail.replyallcc boolean If set to "true", the MimeMessage reply method will put all recipients except the original sender in the Cc list of the newly constructed message. Normally, recipients in the To header of the original message will also appear in the To list of the newly constructed message.

The following properties are supported by the EE4J implementation of Jakarta Mail, but are not currently a required part of the specification. These must be set as System properties. The names, types, defaults, and semantics of these properties may change in future releases.

Jakarta Mail implementation System properties
Name Type Description
mail.mime.base64.ignoreerrors boolean If set to "true", the BASE64 decoder will ignore errors in the encoded data, returning EOF. This may be useful when dealing with improperly encoded messages that contain extraneous data at the end of the encoded stream. Note however that errors anywhere in the stream will cause the decoder to stop decoding so this should be used with extreme caution. The default is false.
mail.mime.foldtext boolean If set to "true", header fields containing just text such as the Subject and Content-Description header fields, and long parameter values in structured headers such as Content-Type will be folded (broken into 76 character lines) when set and unfolded when read. The default is true.
mail.mime.setcontenttypefilename boolean If set to "true", the setFileName method will also set the name parameter on the Content-Type header to the specified filename. This supports interoperability with some old mail clients. The default is true.
mail.mime.setdefaulttextcharset boolean When updating the headers of a message, a body part with a text content type but no charset parameter will have a charset parameter added to it if this property is set to "true". The default is true.
mail.mime.parameters.strict boolean If set to false, when reading a message, parameter values in header fields such as Content-Type and Content-Disposition are allowed to contain whitespace and other special characters without being quoted; the parameter value ends at the next semicolon. If set to true (the default), parameter values are required to conform to the MIME specification and must be quoted if they contain whitespace or special characters.
mail.mime.applefilenames boolean Apple Mail incorrectly encodes filenames that contain spaces, forgetting to quote the parameter value. If this property is set to "true", Jakarta Mail will try to detect this situation when parsing parameters and work around it. The default is false. Note that this property handles a subset of the cases handled by setting the mail.mime.parameters.strict property to false. This property will likely be removed in a future release.
mail.mime.windowsfilenames boolean Internet Explorer 6 incorrectly includes a complete pathname in the filename parameter of the Content-Disposition header for uploaded files, and fails to properly escape the backslashes in the pathname. If this property is set to "true", Jakarta Mail will preserve all backslashes in the "filename" and "name" parameters of any MIME header. The default is false. Note that this is a violation of the MIME specification but may be useful when using Jakarta Mail to parse HTTP messages for uploaded files sent by IE6.
mail.mime. ignoreunknownencoding boolean If set to "true", an unknown value in the Content-Transfer-Encoding header will be ignored when reading a message and an encoding of "8bit" will be assumed. If set to "false", an exception is thrown for an unknown encoding value. The default is false.
mail.mime.uudecode. ignoreerrors boolean If set to "true", errors in the encoded format of a uuencoded document will be ignored when reading a message part. If set to "false", an exception is thrown for an incorrectly encoded message part. The default is false.
mail.mime.uudecode. ignoremissingbeginend boolean If set to "true", a missing "being" or "end" line in a uuencoded document will be ignored when reading a message part. If set to "false", an exception is thrown for a uuencoded message part without the required "begin" and "end" lines. The default is false.
mail.mime. ignorewhitespacelines boolean Normally the header of a MIME part is separated from the body by an empty line. This System property may be set to "true" to cause the parser to consider a line containing only whitespace to be an empty line. The default value of this property is false.
mail.mime. ignoremultipartencoding boolean The MIME spec does not allow body parts of type multipart/* to be encoded. The Content-Transfer-Encoding header is ignored in this case. Setting this System property to "false" will cause the Content-Transfer-Encoding header to be honored for multipart content. The default value of this property is true.
mail.mime.allowencodedmessages boolean The MIME spec does not allow body parts of type message/* to be encoded. The Content-Transfer-Encoding header is ignored in this case. Some versions of Microsoft Outlook will incorrectly encode message attachments. Setting this System property to "true" will cause the Content-Transfer-Encoding header to be honored for message attachments. The default value of this property is false.
mail.mime.contenttypehandler String In some cases Jakarta Mail is unable to process messages with an invalid Content-Type header. The header may have incorrect syntax or other problems. This property specifies the name of a class that will be used to clean up the Content-Type header value before Jakarta Mail uses it. The class must have a method with this signature: public static String cleanContentType(MimePart mp, String contentType) Whenever Jakarta Mail accesses the Content-Type header of a message, it will pass the value to this method and use the returned value instead. The value may be null if the Content-Type header isn't present. Returning null will cause the default Content-Type to be used. The MimePart may be used to access other headers of the message part to determine how to correct the Content-Type. Note that the Content-Type handler doesn't affect the getHeader method, which still returns the raw header value. Note also that the handler doesn't affect the IMAP provider; the IMAP server is responsible for returning pre-parsed, syntactically correct Content-Type information.
mail.mime.address.usecanonicalhostname boolean Use the InetAddress.getCanonicalHostName method to determine the host name in the InternetAddress.getLocalAddress method. With some network configurations, InetAddress.getCanonicalHostName may be slow or may return an address instead of a host name. In that case, setting this System property to false will cause the InetAddress.getHostName() method to be used instead. The default is true.

The current implementation of classes in this package log debugging information using Logger as described in the following table:

Jakarta Mail Loggers
Logger Name Logging Level Purpose
jakarta.mail.internet FINE General debugging output