Pergunta de entrevista da empresa HCLTech

1st round: --> How to write Immutable class ? --> one line defination of, what is Collection and implement a HashMap class. Iterate over it through iterator. --> Exception which will be thown while iterating, if the there are no elements to iterate. --> Find duplicate element and remove the same. I implemeted through ArrayList. --> Diffrerence between fail fast and fail sare iterator. etc.. 2nd Round: We use Struts2 in our project so...architecture of Struts2 Interceptors how validation happens how exception is handeled through JSP basic sql queries