elasticsearch - Api's to compare text in java -

i have web-service in java, used various services insert data in mongodb. since data duplicate, came solution make key-value pair of data , check it, if present, before inserting in mongodb. comparing many string difficult task , take lot of time.

1. do have lib/api's available faster comparison.
2. elastic search search, text comparison too?

my string example

"message:wsclient.fetchreservation::ws fetchreservation calledsystem.net.webexception: operation has timed out @ system.web.services.protocols.webclientprotocol.getwebresponse(webrequest request) @ system.web.services.protocols.httpwebclientprotocol.getwebresponse(webrequest request) @ system.web.services.protocols.soaphttpclientprotocol.invoke(string methodname, object[] parameters) @ botwsclient.channeldirectws.yieldgain.ffetchreservation(string strreservationxml) @ botwsclient.wsclient.fetchreservation(string requestxml)"

if text same hash , compare hashes. if don't have many entries sha1 should suffice.

as jonascz said, please update question know if texts same (my solution work) or similar (my solution not working).