10+ Interview Questions and Answers

Use ORDER BY clause in SQL to sort employees based on salary.

• Use SELECT statement with ORDER BY clause

• Specify the column name 'salary' after ORDER BY

• Use ASC or DESC keyword to specify ascending or descending order

Java 8 introduced new features like lambda expressions, functional interfaces, and streams for more concise and efficient coding.

• Lambda expressions allow for more concise code by enabling functional programming.

• Functional interfaces are interfaces with a single abstract method, which can be implemented using lambda expressions.

• Streams provide a way to process collections of objects in a functional style, allowing for parallel processing and improved performance.

• Examples: Usin...read more

To reverse a string, iterate through the characters and swap the first and last characters until reaching the middle.

• Create a function that takes a string as input

• Initialize two pointers, one at the beginning and one at the end of the string

• Swap the characters at the two pointers and move them towards the center until they meet

String is immutable in order to ensure data integrity and security.

• Immutable strings prevent accidental modification of data

• Immutable strings allow for safe sharing of data between different parts of a program

• Immutable strings help in thread safety and concurrent programming

• Example: String str = "hello"; str.concat("world"); // This will create a new string instead of modifying the original

Comparable is an interface used for natural ordering, while Comparator is an interface used for custom ordering in Java.

• Comparable interface is used to define the natural ordering of objects. It is implemented by the class whose objects are to be compared.

• Comparator interface is used to define custom ordering of objects. It is implemented by a separate class that compares objects of another class.

• Example: String class implements Comparable interface for natural ordering based...read more

Component communication in Angular involves passing data between components using @Input, @Output, services, and event emitters.

• Use @Input to pass data from parent to child component

• Use @Output and EventEmitter to emit events from child to parent component

• Use services to share data between components that are not directly related

• Use RxJS subjects for more complex communication scenarios

HashMap is a data structure that stores key-value pairs and uses hashing to quickly retrieve values based on keys.

• HashMap internally uses an array of linked lists to store key-value pairs.

• When a key-value pair is added, the key is hashed to determine the index in the array where it will be stored.

• If multiple keys hash to the same index (collision), a linked list is used to store all key-value pairs at that index.

• To retrieve a value, the key is hashed to find the index and the...read more

Arraylist is faster for accessing elements, while linked list is better for frequent insertions and deletions.

• Arraylist uses contiguous memory allocation, allowing for faster access via index. Example: accessing elements by index.

• Linked list uses nodes with pointers to the next element, making it better for frequent insertions and deletions. Example: adding elements to the middle of the list.

• Arraylist has a fixed size, while linked list can dynamically grow in size. Example: ...read more

Annotations in Spring are used to provide metadata about the application's components.

• Annotations are used to configure Spring beans, controllers, services, etc.

• They help in reducing the configuration code and make the code more readable.

• Examples include @Component, @Autowired, @RestController, @Service, etc.

Profiles in Spring Boot allow you to define different configurations for different environments.

• Profiles help in managing configurations for different environments like development, testing, production, etc.

• You can define profiles in application.properties or application.yml using 'spring.profiles.active' property.

• Profiles can be activated using command line arguments, environment variables, or servlet context parameters.

• Example: 'spring.profiles.active=dev' will activate the...read more

Services in Angular are singleton objects that can be used to share data or functionality across components.

• Services are used to encapsulate reusable functionality that can be injected into components or other services.

• They are typically used for data sharing, communication with APIs, or other common tasks.

• Services are defined using the @Injectable decorator in Angular.

• Example: UserService that handles user authentication and data retrieval.

I have 5 years of experience in Java programming.

• 5 years of hands-on experience in Java development

• Proficient in Java programming language

• Worked on various Java projects including web applications and backend systems

I have 5 years of experience in SQL.

• 5 years of hands-on experience with SQL

• Proficient in writing complex SQL queries

• Experience in database design and optimization