This page describes hints and tips for using JavaMail with Gmail. Basic Gmail usage information can be found in the JavaMail FAQ.
Gmail users might want to read the IMAP Issues page in Gmail Help.
To send email using Gmail with a different address than the one you signed in with, see this Gmail help page.
You may need to enable less secure apps to use JavaMail with Gmail.
As of Mar 21, 2011, an old Gmail bug has returned. When reading an attachment, Gmail fails to return all of the data. This occurs because Gmail reports the wrong size for the attachment in the BODYSTRUCTURE response. It reports the size using Unix line terminators instead of the required MIME line terminators. The bug has been reported to Google.
As of Dec 2011, several users have reported an ArrayIndexOutOfBoundsException when accessing some messages in Gmail. This is a bug in Gmail involving Subject headers with embedded newlines. Google expects a fix to be available in mid March 2012.
As of Jan 2012, Gmail has a bug that causes it to fail to return a valid IMAP BODYSTRUCTURE response for messages that include another message as an attachment. Applications may see an exception with a message of “ENVELOPE parse error”. The workaround described in the JavaMail FAQ can be helpful for dealing with such messages. JavaMail 1.4.5 includes a workaround for this Gmail bug.
As of Dec 2012, Gmail has a bug that causes it to return a different value for the getMessageID method than is in the Message-Id header of a message. The returned Message-Id is “canonicalized”. If you need the actual value in the header, use the getHeader method instead. Google has no current plans to fix this bug.
As of Jan 2014, Gmail still only notifies clients of new messages and expunged messages when using IMAP IDLE. Other flag changes are not notified.
As of Aug 2014, Gmail moves expunged messages to the Trash folder. They’re only really removed if expunged from Trash.