As a good Java developer, it is very important to have a thorough knowledge of different Java collections, their specifications and uniqueness. It helps in selecting the right data structure for a particular scenario. In any java interview almost every interviewer checks these skills in the candidate. The reason behind this is that an industry level live project can't be developed without using Java Collections. Moreover, selecting a right collection in a particular scenario becomes very important, because the wrong selection may involve in performance implications in the long term. In this article, we will discuss 'Top 20 Collection Framework In Java Interview Questions' and their answers. Additionally, interviewers often evaluate a candidate's proficiency to analyze trade-offs between different collections and