CognitiveClouds Node JS Developer Interview Questions and Answers

Keywords for thread safe program in Java

• Synchronization using synchronized keyword

• Using volatile keyword for shared variables

• Using atomic classes for thread safe operations

• Using thread safe collections like ConcurrentHashMap

• Using locks and semaphores for synchronization

• Avoiding shared mutable state

• Using immutable objects

• Using thread local variables

Class modification exception occurs when a class is modified after it has been loaded by the JVM.

• This exception is thrown when a class is modified and then reloaded by the JVM.

• It can occur when a class is modified during runtime or when a new version of a class is loaded.

• This exception can be avoided by using a class loader that isolates the classes from each other.

• An example of this exception is when a method is added...read more

Interview questions for Java Developer

• JVM is a virtual machine that executes Java bytecode

• OOPS is a programming paradigm based on objects and classes

• SQL queries are used to retrieve data from a database

• REST API is a web service that uses HTTP requests to access and manipulate data

• Sorting an ArrayList can be done using Collections.sort() method

• Known sorting algorithms include Bubble Sort, Quick Sort, and Merge Sort

Java Developer interview questions covering array list, linkedlist, hashmap, synchronization, abstract vs interface, singleton class, Spring framework, database configuration, and Java 8 features.

• ArrayList and LinkedList differ in terms of implementation, performance, and usage

• HashMap uses hashing to store and retrieve key-value pairs

• Synchronized is used to ensure thread safety and prevent race conditions

• Abstract class...read more

This interview question covers various topics including programming, design patterns, data structures, and exception handling in Java.

• Write a program to generate the Fibonacci series

• Write a program using boolean variables

• Explain the ClassCastException and how to handle it

• Discuss the Singleton design pattern and its implementation with different JDK versions

• Explain abstract classes and interfaces in your current project

• ...read more

I have used the Singleton design pattern in my Java projects.

• Singleton pattern ensures that only one instance of a class is created and provides a global point of access to it.

• It is useful when we want to limit the number of instances of a class to one.

• Example: Creating a Logger class as a Singleton to ensure only one instance is used throughout the application.