Dailyhunt Senior Java Developer interview questions

First interview was telephonic call in which they asked two coding questions, print alternate level nodes of tree and one more array related coding problem. Second round was hangout call in which they asked two coding questions on hackerearth. 1)Search pivot such that left and right should be equal 2)Return string contamination (minimum in lexicographical order) in the given list of strings. Polymorphism related concepts , Java 8 features , Threads , why runnable is better , serial and parallel streams , difference between sql and no sql Some output based questions on constructor , polymorphism.