Apache: James Server

The Apache Java Mail Server Version 3.0 is a 100% pure Java SMTP, IMAP4 and POP3 Mail server designed to be a complete and portable enterprise mail engine solution. Apache James Server is based on currently available open protocols. 
Advantages
a. Standard

• 100% pure Java Mail server designed to be a complete and portable enterprise mail engine solution.
• Supports currently available IETF protocols, including SMTP, LMTP, POP3 and IMAP4.
• Apache James Server is able to store user and message data either in a file-system (Maildir), any JPA-compatible database and even JCR, allowing fast, reliable, even real-time replicated storage.
• Provides a powerful, flexible mail application engine through support for the Apache Mailet API. With its Mailet pipeline architecture, Apache James Server can be used not only to provide standard e-mail services, but also to implement custom e-mail applications.

b. Configurable

• James Server is easy to configure. All configuration files resides in ./conf and ./conf/META-INF folder.
• James sever can be configured for the following:
  • domainlist.xml : Domain List Configuration
  • usersrepository.xml : Users Configuration
  • recipientrewritetable.xml : Recipient Rewrite Table Configuration
  • mailbox.xml : Mailbox Configuration
  • mailrepositorystore.xml : Mail Repository Stores Configuration
  • dnsservice.xml : DNS Service Configuration
  • smtpserver.xml : SMTP Configuration
  • lmtpserver.xml : LMTP Configuration
  • pop3server.xml : POP3 Configuration
  • imapserver.xml : IMAP4 Configuration
  • mailetcontainer.xml : Mailet Container Configuration
  • fetchmail.xml : FetchMail Configuration
  • spring-server.xml : System Configuration
  • james-database.properties : System Configuration
  • META-INF/persistence.xml : System Configuration
  • jmx.properties : System Configuration
  • log4j.properties : See monitoring with log4j section.
  • sqlResources.xml : System Configuration
  • jcr-repository.xml : System Configuration

c. Extensible

• Apache James Server serves as a mail application platform.
• The Apache James Project hosts the Apache Mailet API, and provides the Mailet container. These features make it easy to design, write, and deploy custom applications for mail processing.
• This modularity and ease of customization is one of Apache James' strengths, and can allow administrators to produce powerful applications surprisingly easily.

d. Performance Oriented

• Apache James Server can process more than 100 mails per second. Deployed in production environments and has proven itself to be a robust and high performance mail solution. Tests indicate that version 3.0 is able to maintain a constant mail throughput rate of thousands of messages/minute for continuous periods.