Java Interview

MVC Model View Controller SOLID Design Principles Single Responsibility Principle Open-Closed Principle Liskov Substitution Principle Interface Segregation Principle Dependency Inversion Principle

Design Pattern Creational Design Patterns Factory Pattern Prototype Pattern Builder Pattern Singletons Structural Design Patterns Adapter Pattern Composite Pattern Decorator Pattern Behavioral Design Patterns Strategy Pattern State Pattern

STUPID Practices in Programming S for Singleton T for Tight Coupling U for Untestability P for Premature Optimization I for Indescriptive Naming D for Duplication

Terminology

Composition vs Aggregation

Both are Association

1. Composition: A "owns" B
2. Aggregation: A "uses" B

Network

1. Physical Layer: Ethernet, 802.11
2. Data Link Layer: MAC, ARP, PPP
3. Network Layer: IPv4, IPv6
4. Transport Layer
5. Session Layer
6. Presentation Layer
7. Application Layer: DNS

Statefulness

RESTful Web services are completely stateless. Managing the state of conversation is the complete responsibility of the client itself. The server does not help you with this. Normally, a SOAP Web services are stateless – but you can easily make SOAP API stateful by changing the code on the server.

SDLC

Agile

Agile is a structured and iterative approach to project management and product development. It recognizes the volatility of product development, and provides a methodology for self-organizing teams to respond to change without going off the rails. Today, agile is hardly a competitive advantage. No one has the luxury to develop a product for years or even months in a black box. This means it’s more important than ever to get it right.

Kanban

Kanban is all about visualizing your work, limiting work in progress, and maximizing efficiency(or flow). Kanban teams focus on reducing the time it takes to take a project(or user story) from start to finish. They do this by using a kanban board and continuously improving their flow of work.

Scrum

Scrum teams commit to ship working software through set intervals called sprints. Their goal is to create learning loops to quickly gather and integrate customer feedback. Scrum teams adopt specific roles, create special artifacts, and hold regular ceremonies to keep things moving forward.

DevOps

DevOps

The DevOps is a combination of two words, one is software Development, and second is Operations. This allows a single team to handle the entire application lifecycle, from development to testing, deployment, and operations. DevOps helps us to reduce the gap between software developers, quality assurance (QA) engineers, and system administrators.

DevOps tools such as Git, Ansible, Docker, Puppet, Jenkins, Chef, Nagios and Kubernetes.

1. Automation
2. Collaboration
3. Integration
4. Configuration

Puppet

Puppet is the most powerful configuration management tool in the solar system. It’s the engine that drives your compliance, baseline, drift remediation, and deployment needs. It has always been and always will be open source, with freely downloadable operating system-specific agent packages, a massively scalable server, and data warehousing capabilities via PuppetDB.

Ansible

Ansible is an open-source software provisioning, configuration management, and application-deployment tool enabling infrastructure as code. It runs on many Unix-like systems, and can configure both Unix-like systems as well as Microsoft Windows. It includes its own declarative language to describe system configuration. Ansible was written by Michael DeHaan and acquired by Red Hat in 2015. Ansible is agentless, temporarily connecting remotely via SSH or Windows Remote Management (allowing remote PowerShell execution) to do its tasks.

References

Use MVC, SOLID Principles and Design Patterns in Java Organize Objects With Structural Design Patterns Manage Objects With Behavioral Design Patterns Create Objects With Creational Design Patterns Avoid STUPID Practices in Programming Functions of the OSI Layers SOLID Principles in Java Computer Science Design Pattern Algorithm

DevOps Advantages & Disadvantages Comparing SOAP vs REST APIs REST Architectural Constraints HTTP Status Codes Kanban vs. Scrum HTTP Methods Ansible