folder size and null pointer

How do you know *which* messages are available?

Of course, it's possible to load all messages from a folder, but when 
using start and end parameters, how do you know whether the parameters 
are valid?



getMessages

public Message[] getMessages(int start,
                              int end)
             throws MessagingException

     Returns the messages in the given range (inclusive).

     Parameters:
         start - the number of the first message
         end - the number of the last message

http://www.gnu.org/software/classpathx/javamail/javadoc/javax/mail/Folder.html#getMessages%28int,int%29




thanks,

thufir