This Lectures helped me a lot... Thanks Java Gurus...
https://spring.io/guides/gs/accessing-data-mysql/
https://www.youtube.com/channel/UCYt1sfh5464XaDBH0oH_o7Q
https://www.youtube.com/channel/UC59K-uG2A5ogwIrHw4bmlEg
https://www.youtube.com/watch?v=yrGBtlPLth0 for Vaadin
https://mvnrepository.com