As I understood both Adapter and Proxy patterns make two distinct/different classes/objects compatible with each for communication. And both of them are Structural patterns. I am getting that both ...

I was asked below object oriented system design question in an interview. There are multiple devices like Echo show, Echo dot, Echo tab, Smart microwave, Fire tv stick etc. Echo show - It has dis...

In an interview for some company, I was asked this question. What design patterns do you know...then I was told to write simplest "hello world" application based on MVC Design Pattern. I came up ...

can someone please explain the difference between system design and object oriented design? Object oriented design involves object modeling and uses object oriented concepts such as Abstraction, E...

I am extremely new to object-oriented programming, and am trying to begin learning in python by making a simple card game (as seems to be traditional!). I have done the following example which work...

In one of my projects, I have two "data transfer objects" RecordType1 and RecordType2 that inherit from an abstract class of RecordType. I want both RecordType objects to be processed by the same ...

There are two ways of defining a method for two different classes inheriting the same trait in Scala. sealed trait Z { def minus: String } case class A() extends Z { def minus = "a" } case class B...

I am currently designing a software which needs to manage a certain hardware setup. The hardware setup is as following : System - The system contains two identical devices, and has certain func...

Suppose I already have 2 classes in my code: class SomeOrder { String getOrderId() { return orderId; } } class AnotherOrder { String getOrderId() { return orderId; } } How to create an interf...

I know that Adapter is a structural pattern and Mediator is a behavioral one. But as far I understood, what both of them are doing, is connecting two (or more) other classes which are potentially i...

what are the differences between state chart diagrams, state machine diagrams and state transition diagrams? while at several places i got to learn that state chart diagrams and state machine diagr...

Studying about Generalization and inheritance making me confuse, both gives the same meaning as if something is being inherited..but cant figure out the actual difference.

I understand that a class is essentially a blueprint of an object, but the idea that a class is an 'abstraction' of an object is a little hard for me to wrap my head around... If anyone could tell ...

What is 'Evolutionary Development Methodology' means in the context of Mobile Development (Android)? Is there any similarity to 'Object Oriented Methodology' as well? Does someone have an example...

My question is simple. Today, there are a lot of frameworks for both front-end and back-end which implements MVC (Model-View-Control) architecture. Is 'Controller in MVC' an example for Facade Des...

I know abstract classes are not a feature in Ruby, and surely there is a philosophic reason behind that, but I would like to know if there is way to approach problems that typically are resolved us...

In a recent JavaScript interview I was asked about overloading vs overriding. I know this is a concept in Java. But is there something similar in JavaScript, and if so what would be code examples? ...

I am working on an Android project. I have searched high and low but I can't figure out a good strategy to split and package my code. My problem is that I have Inner Classes that use the main cla...

I have a JAVA class A which has a method foo abstract class A { abstract void foo(); } I also have a derived class of A - MutableA. MutableA is a singleton object indicating that no updat...

What is the difference between sequence diagrams and communication (collaboration) diagrams in UML?

There is a same concept for Strategy Pattern and Inheritance, so I can implement Strategy Pattern with Inheritance that sounds it is simpler and cleaner than Strategy Pattern. Startegy Pattern: c...

System design questions are a type of questions that tech companies tend to ask in the interviews in addition to more common algorithmic and knowledge based questions. This term covers both a...

I keep hearing the term object has behavior and state or just one of them. But what is the difference or what does it mean, and if anyone can give an example I would really appreciate it.

Design patterns represent the best practices used by experienced object-oriented software developers. Design patterns are solutions to general problems that software developers faced during s...

We have a business model that requires, say, different types of vehicles to be identified. For example, motorcycle, boat, yacht, farm equipment, snowmobiles, heavy truck, light truck, passeng...