Java EE (Java Enterprise Edition) General Discussion

I have a schedule job to fetch recent emails from a folder and write those emails into a file (.eml file). But it was taking a long time (5 to 6 minutes to read an email of size 9mb) to finish. Since I am using JavaMail API I set the properties as below , in my code , to improve the performance and this way it was taking very less time (20 seconds).

    props.setProperty("mail.imaps.partialfetch","false");

    props.setProperty("mail.imaps.fetchsize", "1048576");

1. Does this (setting `fetchsize` to a larger value) create any other issues in my application?.

2. Setting `fetchsize` to 1048576 means that my schedule job will take

    this much memory always and remaining memory will be allocated to

    rest of my application. Is my understanding correct here?. If not ,

    could someone help me understand this better with an example?.

Entire code is as below,

    package com.indiscover;

    import java.io.File;

    import java.io.FileOutputStream;

    import java.io.IOException;

    import java.io.OutputStream;

    import java.util.Properties;

    import javax.mail.Flags;

    import javax.mail.Folder;

    import javax.mail.Message;

    import javax.mail.MessagingException;

    import javax.mail.NoSuchProviderException;

    import javax.mail.Session;

    import javax.mail.Store;

    import javax.mail.search.FlagTerm;

    public class ReadMail {

    public static void main(String[] args) throws InterruptedException, IOException {

    String protocol="imaps";

    String emailAddress = "email_id";

    String password = "password";

    Properties props = new Properties();

    props.setProperty("mail.store.protocol", protocol);

    props.setProperty("mail.imaps.socketFactory.class", "javax.net.ssl.SSLSocketFactory");

        props.setProperty("mail.imaps.socketFactory.fallback", "false");

        props.setProperty("mail.imaps.port", "993");

        props.setProperty("mail.imaps.socketFactory.port", "993");

        props.setProperty("mail.imaps.partialfetch","false");

        props.setProperty("mail.imaps.fetchsize", "1048576");

    Session session = Session.getInstance(props, null);

    try {

    Store store = session.getStore(protocol);

    store.connect("imap-mail.outlook.com", emailAddress, password);

    Folder inbox = store.getFolder("Archive/Test");

    inbox.open(Folder.READ_WRITE);

    //search for all "unseen" messages

    Flags recent = new Flags(Flags.Flag.RECENT);

    FlagTerm recentFlagTerm = new FlagTerm(recent, true);

    Message messages[] = inbox.search(recentFlagTerm);

    for (int i = 0; i < messages.length; i++) {

    Message message = messages[i];

    String subject = message.getSubject();

    processSaveToFile(message,subject);

    }

    inbox.close(false);

    store.close();

    }catch (NoSuchProviderException ex) {

                System.out.println("No provider.");

                ex.printStackTrace();

            } catch (MessagingException ex) {

                System.out.println("Could not connect to the message store.");

                ex.printStackTrace();

            }

    }

    private static void processSaveToFile (Message msg, String subject) throws MessagingException, IOException

    {

       String whereToSave = "/Users/XXX/Documents/" + "some_random_name" + ".eml";

       OutputStream out = new FileOutputStream(new File(whereToSave));

       try {

           msg.writeTo(out);

       }

       finally {

           if (out != null) { out.flush(); out.close(); }

       }

    }

    }