How to check mail address is exists or not?

Thank you all for your responses.

I am able to solve my problem through MX Record checking .

I used this Link to resolve the problem. May this also be useful for someone.

Hashtable env = new Hashtable();
env.put("java.naming.factory.initial",
             "com.sun.jndi.dns.DnsContextFactory");
DirContext ictx = new InitialDirContext( env );
Attributes attrs = ictx.getAttributes
                       ( hostName, new String[] { "MX" });
Attribute attr = attrs.get( "MX" );
if (( attr == null ) || ( attr.size() == 0 )) {
   attrs = ictx.getAttributes( hostName, new String[] { "A" });
   attr = attrs.get( "A" );
   if( attr == null )
         throw new NamingException
                  ( "No match for name '" + hostName + "'" );
}

Thank you.

The only way to confirm an email address is to send an email to it and require the user to follow a (unique) link in the email back to your website.