JPMorgan Interview Questions

Face-To-Face: June 2018
Exp Level: 5-7 Years

Round 1:
a=10 a=20
b=30 b=40
c=40 c=30
d=20 d=10
Swap without using third variable

Concurrent modification exception
ConcurrentHashMap,
 and details
minor and major exception
Garbage collection algo
classloaders, bootstrap classloader and use
"     Utsav Garg.     "- trim without using trim function
Write Iterator on Hashmap
Why we cannot create object of abstract class
Can we create constructor of abstract class.
Difference between interface and abstract class
Find duplicate values using sql query in column
What is error and give example
Exception hierarchy
Aggregation and composition
How we create threads
Types of memory in java
String pool in java
Write customised exception example.
What is SQL Joins and example
example of marker interface and its benefit

Round 2
Features of Java 8
Functional interface vs interface vs abstract class
Lambda expression and write example of it.
Critical section in threads
What is synchronization
Volatile variable
Given 5 lifts and people want to use lift. Whats the optimised approach so that people can reach respective floors quickly
What is atomic variable.
What is thread pool
What is executor framework and its interfaces.

Round 3
About your experience
There is a search box and user is searching something and result is too slow. How will you find root cause. Possible root cause and approach to solve it.
Find duplicate in a column using SQL queries.