Building a simple IMAP Client that displays the subject of the messages in the “inbox” Folder using Maven (I just like Maven).

Project Setup / Maven

  1. Create a new Maven project

    mvn archetype:create -DgroupId=com.hascode.imap -DartifactId=imap-client

  2. Edit your pom.xml and add some dependencies

    <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.hascode.imap</groupId>
     <artifactId>imap-client</artifactId>
     <version>0.0.1-SNAPSHOT</version>
     <dependencies>
         <dependency>
             <groupId>junit</groupId>
             <artifactId>junit</artifactId>
             <version>4.8.1</version>
         </dependency>
         <dependency>
             <groupId>javax.mail</groupId>
             <artifactId>mail</artifactId>
             <version>1.4.2</version>
         </dependency>
     </dependencies>
</project>

Creating the E-Mail Client

  1. Create a package .. something like com.hascode.imap.client ;)

  2. Create a simple mail client using javax.mail in a class named ImapClient

    package com.hascode.imap.client;

import javax.mail.Folder;
import javax.mail.Message;
import javax.mail.MessagingException;
import javax.mail.Session;
import javax.mail.Store;

public class ImapClient {
    private Session session = null;
    private Store store = null;
    private String host = null;
    private String userName = null;
    private String password = null;

    public ImapClient(String host, String userName, String password){
        this.host = host;
        this.userName = userName;
        this.password = password;
    }

    public boolean getMail() throws MessagingException {
        session = Session.getDefaultInstance(System.getProperties(),null);
        //        session.setDebug(true);
        System.out.println("get store..");
        store = session.getStore("imaps");
        System.out.println("connect..");
        store.connect(this.host, this.userName, this.password);
        System.out.println("get default folder ..");
        Folder folder = store.getDefaultFolder();
        folder = folder.getFolder("inbox");
        folder.open(Folder.READ_ONLY);
        System.out.println("reading messages..");
        Message[] messages = folder.getMessages();
        for(Message m:messages){
          System.out.println(m.getSubject());
        }
        return false;
    }
}

  3. Test the result in an unit test or a test class like this one

    package com.hascode.imap.client;

import javax.mail.MessagingException;

public class Main {

    public static void main(String[] args) {
        ImapClient c = new ImapClient("<yourhostname>", "<yourusername>","<yourpassword>");
        try {
        c.getMail();
        } catch (MessagingException e) {
          e.printStackTrace();
        }
    }
}

Debugging an E-Mail Session

If something goes wrong – use the debugging feature in the session object:

session.setDebug(true);

Creating an E-Mail Server in Java

If you’re interested in creating an e-mail server in java for testing please feel free to take a look at my tutorial: “https://www.hascode.com/2012/07/integration-testing-imap-smtp-and-pop3-with-greenmail/[Integration Testing IMAP, SMTP and POP3 with GreenMail]“.

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