Javamail IMAP connection with Gmail drops after a random duration

Question

I'm using Javamail to authenticate into gmail imap server and fetch messages headers for complete mailbox one at a time and index locally. For inboxes which have few messages, this works fine. For inboxes with messages more than 10k in general, javamail imap connection gets dropped (possibly by server). The point to note is that this duration is random.

Since I am continuously fetch message headers one after one there isn't a time where the connection is idle for a long, so it can't be a timeout.

------------------------------CODE--------------------------------

IMAPSSLStore imapSslStore = connectToImap("imap.googlemail.com", 993, email, oauthToken,  oauthTokenSecret, getMyConsumer(), true);
System.out.println("Successfully authenticated to IMAP.\n");
Folder inbox = imapSslStore.getFolder("[Gmail]/All Mail");
inbox.open(Folder.READ_ONLY);

Message messages[] = inbox.getMessages();

for(Message message:messages) {
  System.out.println(message);
  System.out.println("MSG NO:"+message.getMessageNumber());
  System.out.println("FROM:"+message.getFrom().toString());
}

-------------------------------CODE--------------------------------------------

Exception trace:

[java] javax.mail.FolderClosedException: * BYE JavaMail Exception: java.io.IOException: **Connection dropped by server?**

[java] at org.apache.tools.ant.taskdefs.ExecuteJava.execute(ExecuteJava.java:194)
[java] at org.apache.tools.ant.taskdefs.Java.run(Java.java:747)
[java] at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:201)
[java] at org.apache.tools.ant.taskdefs.Java.execute(Java.java:104)
[java] at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
[java] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[java] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[java] at java.lang.reflect.Method.invoke(Method.java:597)
[java] at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:105)
[java] at org.apache.tools.ant.Task.perform(Task.java:348)
[java] at org.apache.tools.ant.Target.execute(Target.java:357)
[java] at org.apache.tools.ant.Target.performTasks(Target.java:385)
[java] at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1329)
[java] at org.apache.tools.ant.Project.executeTarget(Project.java:1298)
[java] at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
[java] at org.apache.tools.ant.Project.executeTargets(Project.java:1181)
[java] at org.apache.tools.ant.Main.runBuild(Main.java:698)
[java] at org.apache.tools.ant.Main.startAnt(Main.java:199)
[java] at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
[java] at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)
[java] Caused by: javax.mail.FolderClosedException: * BYE JavaMail Exception: java.io.IOException: Connection dropped by server?
[java] at com.sun.mail.imap.IMAPMessage.loadEnvelope(IMAPMessage.java:1198)
[java] at com.sun.mail.imap.IMAPMessage.getFrom(IMAPMessage.java:233)
[java] at com.google.code.samples.xoauth.XoauthAuthenticator.main(XoauthAuthenticator.java:209)
[java] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[java] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[java] at java.lang.reflect.Method.invoke(Method.java:597)
[java] at org.apache.tools.ant.taskdefs.ExecuteJava.run(ExecuteJava.java:217)
[java] at org.apache.tools.ant.taskdefs.ExecuteJava.execute(ExecuteJava.java:152)
[java] ... 20 more
[java] --- Nested Exception ---
[java] javax.mail.FolderClosedException: * BYE JavaMail Exception: java.io.IOException: Connection dropped by server?
[java] at com.sun.mail.imap.IMAPMessage.loadEnvelope(IMAPMessage.java:1198)
[java] at com.sun.mail.imap.IMAPMessage.getFrom(IMAPMessage.java:233)
[java] at com.google.code.samples.xoauth.XoauthAuthenticator.main(XoauthAuthenticator.java:209)
[java] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[java] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[java] at java.lang.reflect.Method.invoke(Method.java:597)
[java] at org.apache.tools.ant.taskdefs.ExecuteJava.run(ExecuteJava.java:217)
[java] at org.apache.tools.ant.taskdefs.ExecuteJava.execute(ExecuteJava.java:152)
[java] at org.apache.tools.ant.taskdefs.Java.run(Java.java:747)
[java] at org.apache.tools.ant.taskdefs.Java.executeJava(Java.java:201)
[java] at org.apache.tools.ant.taskdefs.Java.execute(Java.java:104)
[java] at org.apache.tools.ant.UnknownElement.execute(UnknownElement.java:288)
[java] at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
[java] at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
[java] at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
[java] at java.lang.reflect.Method.invoke(Method.java:597)
[java] at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:105)
[java] at org.apache.tools.ant.Task.perform(Task.java:348)
[java] at org.apache.tools.ant.Target.execute(Target.java:357)
[java] at org.apache.tools.ant.Target.performTasks(Target.java:385)
[java] at org.apache.tools.ant.Project.executeSortedTargets(Project.java:1329)
[java] at org.apache.tools.ant.Project.executeTarget(Project.java:1298)
[java] at org.apache.tools.ant.helper.DefaultExecutor.executeTargets(DefaultExecutor.java:41)
[java] at org.apache.tools.ant.Project.executeTargets(Project.java:1181)
[java] at org.apache.tools.ant.Main.runBuild(Main.java:698)
[java] at org.apache.tools.ant.Main.startAnt(Main.java:199)
[java] at org.apache.tools.ant.launch.Launcher.run(Launcher.java:257)
[java] at org.apache.tools.ant.launch.Launcher.main(Launcher.java:104)

I'm using the standalone version of javamail (1.4.3) I've struggling to fix this for a while now. Any help is appreciated.

Answer 1

You need to catch the FolderClosedException, then try to connect again. I've faced that issue and solved it by the following code:

 catch (FolderClosedException ex) {
                        ex.printStackTrace();
                        ConnectPop3(Username, Password);
                        if (!folder.isOpen()) {
                            folder.open(Folder.READ_ONLY);
                            messages = folder.getMessages();
                        }
                    }