2019.5 Recruitment of meituan interns （java software development ） Face the
Garbage collection （ Judge whether the garbage should be recycled 、 Recovery algorithm 、 Recyclers ）
Class loading , How to ensure that the class is loaded only once （ Class loading steps 、 Parent delegate mechanism ）
hashmap How to realize automatic capacity expansion
How to implement multiple threads at the same time
Parameters of thread pool
Common data structure
springboot
mybatis
Database isolation level
Algorithm ： The intersection of two ordered lists
https://www.cnblogs.com/aspirant/p/10012840.html