59 interview questions for developers (2024)

Easy

13 votes1468 runs0 comment

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

IT Architect

OOP

javascript

undefined

Eric Hostaleryat Dec 3, 2021

Hard

8 votes550 runs0 comment

Overrided method visibility must be the same or less restrictive than the inherited method.

IT Architect

OOP

visibility

inheritance

Samuelat Mar 28, 2022

Easy

8 votes484 runs0 comment

You need to develop a class for which there should be only one instance throughout your application. Which design pattern should you use for this?

IT Architect

OOP

design pattern

singleton

Elieat Mar 28, 2023

Hard

7 votes1346 runs0 comment

Can we extend an abstract class in Java?

IT Architect

OOP

abstract

class

Eric Hostaleryat Dec 3, 2021

Easy

7 votes570 runs0 comment

Inheritance in OOP.

IT Architect

OOP

inheritance

methods

Samuelat Mar 28, 2022

Medium

4 votes1385 runs0 comment

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

IT Architect

OOP

javascript

undefined

Eric Hostaleryat Dec 3, 2021

Easy

4 votes561 runs0 comment

Can a class implements several interfaces ?

IT Architect

OOP

interfaces

inheritance

Samuelat Mar 28, 2022

Medium

4 votes536 runs1 comment

When can you do a+b in OOP ?

IT Architect

OOP

operator overloading

classes

Samuelat Mar 28, 2022

Medium

3 votes1358 runs0 comment

Implement the interface IEmailFormatter for the classes Person, Company, and ListOfPerson, which has a method GetEmailContent()

IT Architect

OOP

interfaces

classes

Eric Hostaleryat Mar 13, 2023

Easy

3 votes1337 runs0 comment

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

IT Architect

OOP

undefined

Eric Hostaleryat Dec 3, 2021

Easy

3 votes1335 runs0 comment

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

IT Architect

OOP

javascript

undefined

Eric Hostaleryat Dec 3, 2021

Hard

3 votes1331 runs1 comment

Implement the registration method on class A in a virtual way,Override the registration method on classes A1 and A2 when implementing these classes

IT Architect

OOP

classes

inheritance

Eric Hostaleryat Dec 3, 2021

Medium

3 votes1296 runs1 comment

Can an interface inherit from another interface?

IT Architect

OOP

interfaces

Vincent Cotroat Dec 3, 2021

Hard

2 votes1417 runs0 comment

Which design pattern allows to dynamically add responsibilities to an object?

IT Architect

OOP

design pattern

object

Eric Hostaleryat Sep 19, 2022

Easy

2 votes1365 runs0 comment

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

IT Architect

OOP

javascript

undefined

Eric Hostaleryat Dec 3, 2021

Medium

2 votes486 runs0 comment

Explain the difference between overriding and overloading in OOP.

IT Architect

OOP

methods

inheritance

Samuelat Mar 28, 2022

Easy

2 votes182 runs0 comment

Inheritance, polymorphism and encapsulation

IT Architect

OOP

inheritance

polymorphism

encapsulation

Monemat Nov 3, 2023

Hard

1 vote1366 runs1 comment

What is the default value of a field in a class in Java?

IT Architect

OOP

constructor

object

Eric Hostaleryat Dec 3, 2021

Hard

1 vote1341 runs0 comment

What are the public methods of the class `Person`?

IT Architect

OOP

methods

visibility

Eric Hostaleryat Dec 3, 2021

Medium

1 vote520 runs2 comments

In this code, the class B extends the class A. The class B overrides the method talk() from the class A. The object b is an instance of the class B. The object a is an instance of the class A. The object a is assigned to the object b. The object a calls the method talk(). The method talk() from the class B is called.

IT Architect

OOP

inheritance

polymorphism

Samuelat Mar 28, 2023

59 interview questionsfor developers (2024)

Test your developer skills before an interview with 59 corrected questions on 80+ topics. Beginner, Intermediate or Expert level.

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

Overrided method visibility must be the same or less restrictive than the inherited method.

You need to develop a class for which there should be only one instance throughout your application. Which design pattern should you use for this?

Can we extend an abstract class in Java?

Inheritance in OOP.

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

Can a class implements several interfaces ?

When can you do a+b in OOP ?

Implement the interface IEmailFormatter for the classes Person, Company, and ListOfPerson, which has a method GetEmailContent()

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

Implement the registration method on class A in a virtual way,Override the registration method on classes A1 and A2 when implementing these classes

Can an interface inherit from another interface?

Which design pattern allows to dynamically add responsibilities to an object?

Is the following code valid? class Person { constructor(name, age) { this.name = name; this.age = age; } } const person = new Person('John', 20); console.log(person.name); console.log(person.age);

Explain the difference between overriding and overloading in OOP.

Inheritance, polymorphism and encapsulation

What is the default value of a field in a class in Java?

What are the public methods of the class `Person`?