In general, applications should not need to use the classes in this package directly. Instead, they should use the APIs defined by javax.mail package (and subpackages). Applications should never construct instances of POP3Store or POP3Folder directly. Instead, they should use the Session method getStore to acquire an appropriate Store object, and from that acquire Folder objects.
POP3 Provider for JavaMail http://injektilo.org/pop3mail.html
javax.mail.internet.*
就可以。
protocol=imap; type=store; class=com.sun.mail.imap.IMAPStore; vendor=Sun Microsystems, Inc;
# JavaMail SMTP provider Sun Microsystems, Inc
protocol=smtp; type=transport; class=com.sun.mail.smtp.SMTPTransport; vendor=Sun Microsystems, Inc;
# JavaMail POP3 provider Sun Microsystems, Inc
protocol=pop3; type=store; class=com.sun.mail.pop3.POP3Store; vendor=Sun Microsystems, Inc;