Not Able to Set SEEN flag to mails read from gmail

I am using IMAP protocol to connet to my gmail account.

My application fails at this line. message.setFlag(Flags.Flag.SEEN, true);

And the log details are as follows:

[java] ---- exception report ----------------------------------------------------------
 [java] An error Occured while reading mail
 [java] Exception: javax.mail.MessagingException
 [java] Message: A10 NO STORE attempt on READ-ONLY folder (Failure)
 [java] ---- cause ---------------------------------------------------------------------
 [java] Exception: com.sun.mail.iap.CommandFailedException
 [java] Message: A10 NO STORE attempt on READ-ONLY folder (Failure)
 [java] ---- stack trace ---------------------------------------------------------------
 [java] com.sun.mail.iap.CommandFailedException: A10 NO STORE attempt on READ-ONLY folder (Failure)
 [java] com.sun.mail.ia开发者_开发知识库p.Protocol.handleResult(Protocol.java:294)
 [java] com.sun.mail.imap.protocol.IMAPProtocol.storeFlags(IMAPProtocol.java:1294)
 [java] com.sun.mail.imap.protocol.IMAPProtocol.storeFlags(IMAPProtocol.java:1279)
 [java] com.sun.mail.imap.IMAPMessage.setFlags(IMAPMessage.java:843)
 [java] javax.mail.Message.setFlag(Message.java:565)

Any help will be appreciated.

Thanks, Kumaraswamy.N

It looks like you opened your folder as READ_ONLY. Make sure you are doing

folder.open(Folder.READ_WRITE)

when you open your folder.

BTW POP protocol doesn't recognize Flags. So I'm surprised it works for POP since you should be getting an IllegalWriteException when using POP. Regardless, message.setFlag(...) won't do anything with POP.

message.setFlag(Flags.Flag.SEEN, true);

This is a writ operation which you are performing on your code.

As @Nikordaris said give writ permission like this:

folder.open(Folder.READ_WRITE)