Help me, to send a mail with attachment using JavaAPI

I am facing some problem with Java Mail API
when i am sending the mail. Can you correct me.

Problem: When sending an attachment text/plain, MyText.txt file as a part of the
message using Java Mail API, the contents of the file MyText.txt are getting
displayed as part of the message when I am sending mail to my HotMail account.
Is this problem with HotMail, or my Java class itself.

The following are the classes i am using
1. MimeMessage for creating message object
2. MimeBodypart: to define a container
3. MimeMultiPart:For handling different parts of the message
4. FileDataSource: to wrap the file
5. DataHandler: to set the message content
I am not setting any content-type.
I am not setting any content-disposition

If this information is not enough, i will send the java code, please mail me.

Thanks for reading my mail.
Please reply me

Regards Jagannadh