When i type site:xyz.com or site:http://xyz.com all the links shows in google but when i type site:www.xyz.com or site:http://www.xyz.com it says Your search - site:http://www.xyz.com - did not match any documents. Is there any problem with my site url ! Any disadvantage ... ! Thanks in advance !
Your site is most likely sandboxed. Sandboxing happens if your site is very new, in this case it will come out on its own or if the site was detected to have malware on it and in this case you will have to remove the bad stuff.
Your site will only come up for the relevant keyword searches, ie the keywords you have targeted doing seo.
Did u set your preferred domain: without www or with www? You can do this from google webmaster tools. Before that add and verify both versions: www. and without www.