⭐Question Set 2

Java Programming

• What is covariant?

• Real life examples of features of OOPS.

• What are wrapper classes?

• Write a implementation for Predicate functional interface

• Functional Interface implementation Dynamically with Lambda

• Junit Test case for addition of two numbers

• Difference between Java 7 and Java 8.

• How to clone an object in Java?

• Can a static inner class be present within a non-static class?

• When do you get the ClassNotFound error in Java?

• Does Java have pointers or references?

• What is the difference between i++ and ++i in Java?

• What is the Collections class and Arrays class in Java?

• Maven exclusion and scope related questions

• Reflection in Java.

• What is an Enum in Java?

• What is the Map collection in Java?

• Difference between Enumerator and Iterator in Java

• What is the difference between a static block and instance block in Java?

• What is Generics in Java and how to implement mutable and immutable objects?

Collections & Data Structures

• Explain List, ArrayList and Set

• Comparison of HashSet and HashMap in Java

• What is the internal working of HashMap and HashSet in Java?

• What is collision in HashMap/Hashtable in Java?

• What is the use of Optional feature in Java 8? Can you provide an example?

• What is the hierarchy of Collection and Exception classes in Java?

Strings & Memory Management

• String compare and string constant pool questions

• How to check equality of two string literals

• Why is String immutable if it can be assigned a new value?

• How string variables are stored in memory?

• What happens if a new variable is created with the same value?

• How memory is allocated to String?

Exception Handling

• Explain ConcurrentModificationException

• Revisit checked and unchecked exceptions.

• Exception hierarchy and why Throwable is used.

• How to create custom exceptions.

• Types of exception handling.

• Checked vs unchecked exceptions.

• Throw vs Throws vs Throwable.

• Deciding between Checked or Unchecked exceptions for user defined exceptions

Java 8 Features

• Parallel Stream

• Functional Interface

• Difference between Stream API and Collections framework

• Why static methods introduced in Interface from Java 8?

• Can one functional interface extend another functional interface?

• What is the difference between intermediate and terminal operation in stream API?

• Map and filter

• Functional Interface

• Stream API

• How to group elements in a stream using GroupBy?

• How to sort elements in a stream using Sorted?

• What are Terminal and Intermediary operations in the Stream API?

Concurrency

• What is future in Executor framework

• Difference between submit and execute methods

• How to use execute methods

• Synchronization topic: serialized vs. synchronized and ways to achieve synchronization.

• Threads: Thread limit, executor, etc.

Design Patterns

• Explain factory design pattern

• What are design patterns

• Explain design patterns used in your application with code

SQL

• SQL question to find the student with maximum cost

Microservices

• What is Microservice

• Command used to access a container

• Kubernetes commands

• What is Kubernetes and its function

• Producer, consumer, predicate, supplier

• How to create and manage JMS.

• What is Callable/Future and how to achieve async in Java?

• What is ThreadPoolExecutor and how to manage threads using it?

• How to get the result from an async operation?

• How to handle exceptions from a Runnable?

• What is ExecutorService and how does it differ from Error and Exception?

• How to handle an OutOfMemoryError and what are the workarounds for it?

Coding

• Write code to get customer accounts by id

• What is REST API

• Conflicting questions about REST methods like POST for response data

• Idempotent in REST API with example

• Java Lambda expression - program to get employees from a List of List of employees whose age is less than 40

• Array Operations: Second max value from array

• Design Patterns: Immutability, singleton

JPA

• What is JPA

• What is Entity

• What is Entity scan

• ORM framework used

• What is @Qualifier annotation

• What is @Required annotation

• How to use the remove in JPA cascading operations

Git

• Git merge conflict scenarios

• Git commit scenarios

JUnit & Testing

• What is Mockito and why it is used

• Explain Junit testing with example

• What is Sonarqube

Miscellaneous

• What is Normalization in SQL (1NF, 2NF, BCNF, etc.)?

• What is the difference between Pointers and References in C++?