Read a text file & write the duplicate records to another text file in Java

I have an existing text file with a list of book names. I want to read those names & write a second text file with the names of duplicate entries. For example: SamsBookstore.txt might have
And Then It's Spring
Baby Bear Sees Blue
Beach Feet
Jimmy the Greatest!
Boot & Shoe
Baby Bear Sees Blue
Boy & Bot
Cat Tale
Creepy Carrots!
Jimmy the Greatest!

I would want the SamsDuplicates.txt to have:
Baby Bear Sees Blue
Jimmy the Greatest!

I already have some of this code, but i'm not sure if its common to post it in the thread or should i upload a file

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