10+ Pan Gulf Technologies Interview Questions and Answers

The design pattern is used to solve a specific problem in software development.

• Design patterns are reusable solutions to common problems in software development.

• They provide a standard way to solve a problem that can be adapted to different situations.

• Examples of design patterns include Singleton, Factory, Observer, and Decorator.

• Using design patterns can improve code quality, maintainability, and scalability.

Design patterns are reusable solutions to common software problems.

• Creational patterns: Singleton, Factory, Abstract Factory

• Structural patterns: Adapter, Decorator, Facade

• Behavioral patterns: Observer, Strategy, Command

• Architectural patterns: Model-View-Controller, Model-View-ViewModel

• Concurrency patterns: Thread Pool, Producer-Consumer

• Examples: Singleton ensures only one instance of a class exists, Factory creates objects without exposing the instantiation logic, Observer al...read more

Factory Method Pattern

• Defines an interface for creating objects, but lets subclasses decide which class to instantiate

• Encapsulates object creation logic to a separate class

• Useful when a class can't anticipate the type of objects it needs to create

• Example: java.util.Calendar.getInstance()

• Example: javax.xml.parsers.DocumentBuilderFactory.newInstance()

Java8 features include lambda expressions, functional interfaces, streams, and default methods.

• Lambda expressions allow functional programming and simplify code.

• Functional interfaces enable the use of lambda expressions.

• Streams provide a way to process collections of data in a functional way.

• Default methods allow interfaces to have method implementations.

• Other features include the Date and Time API, Nashorn JavaScript engine, and improved security.

Data structures are used to organize and store data in a way that enables efficient access and modification.

• Data structures can be classified as linear or non-linear

• Examples of linear data structures include arrays, linked lists, and stacks

• Examples of non-linear data structures include trees and graphs

• Data structures can be implemented using various programming languages

• Efficient algorithms for searching, sorting, and manipulating data depend on the choice of data structure

Concurrent HashMap is thread-safe and allows concurrent access, while HashMap is not thread-safe.

• Concurrent HashMap is suitable for multi-threaded environments where multiple threads can access and modify the map concurrently.

• HashMap is not thread-safe and can lead to data corruption if accessed concurrently by multiple threads.

• Concurrent HashMap uses internal locking mechanisms to ensure thread safety, while HashMap does not provide such mechanisms.

• Example: In a web applicat...read more

Multi threading is a technique to execute multiple threads concurrently in a single process.

• Multi threading improves application performance by utilizing multiple CPU cores.

• It requires careful synchronization to avoid race conditions and deadlocks.

• Java provides built-in support for multi threading through the Thread class and Runnable interface.

• Thread pools can be used to manage and reuse threads efficiently.

• Multi threading can be used in various applications such as web serv...read more

Java 8 introduced several new features including lambda expressions, streams, and default methods.

• Lambda expressions allow for functional programming and simplify code.

• Streams provide a way to process collections of data in a functional way.

• Default methods allow for adding new methods to interfaces without breaking existing implementations.

• Other features include the Optional class, Date and Time API, and Nashorn JavaScript engine.

Partitioning a large database involves dividing the data into smaller chunks to improve performance and manageability.

• Identify key columns for partitioning, such as date ranges or customer IDs.

• Choose a partitioning strategy, such as range partitioning or hash partitioning.

• Implement partitioning using database features like table partitioning in Oracle or partitioned tables in PostgreSQL.

Collection's framework is a set of interfaces and classes that provide high-performance, high-quality implementations of data structures.

• Provides interfaces like List, Set, Map for storing and manipulating collections of objects

• Includes classes like ArrayList, LinkedList, HashSet, HashMap for concrete implementations

• Allows for easy iteration, sorting, searching, and manipulation of collections

• Supports generics to ensure type safety and compatibility

Hooks in React are functions that let you use state and other React features in functional components.

• Hooks were introduced in React 16.8 to allow functional components to have state and lifecycle methods.

• useState() is a hook that allows you to add state to functional components.

• useEffect() is a hook that lets you perform side effects in functional components.

• Custom hooks are reusable functions that can contain stateful logic and be shared across components.