What is the difference between a kernel and a shell?

Vaibhav Kothia May 26, 2023 0 Comments

A kernel is the core of an operating system. It is responsible for managing the resources of the computer, such as memory, processors, and peripherals. It also provides an interface between the user and the hardware. An example of a kernel is the Linux kernel.

A shell is a program that provides an interface for users to interact with the operating system. It interprets commands from the user and passes them to the kernel for execution. An example of a shell is the Bash shell.

What is the difference between an interface and an abstract class?

Vaibhav Kothia May 26, 2023 0 Comments

An interface is a collection of abstract methods and constants that form a common set of base rules for a class to follow. An interface does not contain any implementation code, and it cannot be instantiated. An example of an interface might be a Comparable interface which defines the compareTo() method.

An abstract class is a class that contains both abstract methods (methods without an implementation) and concrete methods (methods with an implementation). An abstract class can be instantiated, and it is often used as a base class from which other classes can inherit. An example of an abstract class might be an Animal class which defines the abstract method makeSound() and the concrete method eat().

What is the difference between a constructor and a method?

Vaibhav Kothia May 26, 2023 0 Comments

A constructor is a special type of method that is used to create an instance of an object. It is invoked when an instance of the object is created and it is used to set up the initial state of the object.

A method is a block of code that performs a specific task and is associated with an object. It is invoked by calling the method on the object.

Example:

Constructor:

public class Car {
private String make;
private String model;

public Car(String make, String model) {
this.make = make;
this.model = model;
}
}

Method:

public class Car {
private String make;
private String model;

public void setMake(String make) {
this.make = make;
}

public void setModel(String model) {
this.model = model;
}
}

What is the difference between MongoDB and a relational database?

Vaibhav Kothia May 26, 2023 0 Comments

MongoDB is a non-relational database, while a relational database is a structured database that uses relations between tables to store and access data.

Example:

MongoDB: A MongoDB database stores data in a flexible JSON-like document structure. Each document can have different fields and data types, and the data can be nested within the document.

Relational Database: A relational database stores data in tables with rows and columns. Each row is a record, and each column is a field within that record. The data in each field must be of the same data type, and the data must be related by a common key.

What is the difference between a protocol and a category?

Vaibhav Kothia May 26, 2023 0 Comments

A protocol is a set of rules that govern how computers communicate with each other. For example, the Transmission Control Protocol (TCP) is a protocol that allows two computers to communicate with each other over the internet.

A category is a way of organizing or grouping related items. For example, a website might have a category for books, and each book would be listed under that category.

What is the difference between call() and apply()?

Vaibhav Kothia May 26, 2023 0 Comments

The main difference between call() and apply() is the way in which arguments are passed to the function.

The call() method takes arguments separately, while the apply() method takes arguments as an array.

Example:

function add(a, b) {
return a + b;
}

// call()
add.call(this, 1, 2); // Output: 3

// apply()
add.apply(this, [1, 2]); // Output: 3