We want to push text from server to all Cisco Jabber client. Is there any API available for this?
Cisco Jabber SDK is best for point to point IM not for IM push from server side.
Edited to add: No, I don't see any XMPP specification for sending a message to all contacts.
If you are familiar with python you can use simple module like slixmpp mathieui/slixmpp · GitHub (it works with IM&Presence)
And as Nicolas suggested you can have a user with a contact-list containing all your users and send messages to all of them inside a script. Another option is to have a MUC (chat room) and to send announces through it (maybe with the help of this same slixmpp).