Difference between javax.mail and javax.mail-api

Question

What is the difference between javax.mail and javax.mail-api ?

I found those from maven repository.

When should each be used?

The software package comes with javax.mail-api but I could not get it work, so I downloaded javax.mail .

Answer 1

javax.mail-api只包含接口， javax.mail包含实现。

Answer 2

When libraries such as the Java Mail API are not published by their authors to Maven Central or other public repository, it's possible that different parties upload them, publishing it with conflicting groupId . It's probably the case for those two you're seeing.

This artifact appears to contain the latest version of all you need to work with the mail api.

Answer 3

AFAIK from experience and looking at maven central ...

When javax.mail: mail is bundled in a 'war' and is also in tomcat 'lib' one gets this error:

java.lang.ClassCastException: javax.mail.Session cannot be cast to javax.mail.Session

Similarly, javax.mail: javax-mail-api contains a Session class and is more than just interfaces. When it is missing one gets this error:

java.lang.NoClassDefFoundError: javax/mail/Authenticator

com.sun.mail: javax-mail is something sun/oracle specific.