Six Dee Telecom Solutions Software Engineer - Java Developer interview questions

Core Java,Collections, Spring core,spring mvc. Asked to write sql queries using joins,cartesian. Some questions were on real time application development, memory leak, performance tuning.

1. Basic core java questions 2. questions o n collections like difference between HashMap and ConcurrentHashMap,internal implementation of HashMap 3.Which collection is used to maintain unique elements 4.When ins ArrayList and LinkedList used 5.Programming questions on threads,synchronization,wait,notify 6. few basic programming questions like find the second highest element of an array without sorting etc 7.Basic linux commands 8. JVM memory structure, what is stack heap etc