java.io.IOException: Unknown encoding:

Exception in thread "main" java.io.IOException: Unknown encoding:
at javax.mail.internet.MimePartDataSource.getInputStream(MimePartDataSource.java:92)
at com.sun.mail.handlers.text_plain.getContent(text_plain.java:59)
at javax.activation.DataSourceDataContentHandler.getContent(DataHandler.java:795)
at javax.activation.DataHandler.getContent(DataHandler.java:542)
at javax.mail.internet.MimeBodyPart.getContent(MimeBodyPart.java:659)
Caused by: javax.mail.MessagingException: Unknown encoding:
at javax.mail.internet.MimeUtility.decode(MimeUtility.java:381)
at javax.mail.internet.MimePartDataSource.getInputStream(MimePartDataSource.java:85)
... 9 more

I find same problem from this
https://github.com/javaee/javamail/pull/312
but ,it seems still not solve

Start with the stack trace at javax.mail.internet.MimeUtility.decode and MimePartDataSource.getInputStream, then review the referenced javaee/javamail pull request #312. A useful outcome is a reproducible case and a clear determination of whether that change addresses the empty or unknown encoding error.

Written by the indexing model from the issue text.