title: Backup of Postgresql database with pg_dump
body: <p>after a search on the internet with no result, I turn to you!
  I would like to create a java program, that if you click on a button, it makes a backup of a database in postgresql.
  I saw that i must use pg_dump but do not understand how to make it work.
  can someone please help me?</p>
  
  <p>thank you!</p>