Software Development & Operations

Question 1

Describe the vanilla structure of an Android project?

Answer 1

Within every Android app, we have five different kinds of files:

1. AndroidManifest.xml - Defines properties of the application.
2. Layout files - Defined via xml.
3. Logic files - Defined in Java and Kotlin
4. Resources - Within the res folder. Contains static variables and static files (like images) for your app.
5. Gradle - Build files for translating code to an APK.

Question 2

What does Gradle do?

Answer 2

Combines all of the development files and builds one single APK file for testing and distribution via Play Store.

Question 3

What is the build.gradle file used for?

Answer 3

Adding dependencies from third party modules (such as YouTube player).

Acts in a similar way to the dependencies property of the package.json file of node.js

Question 4

How do you create an array in Java?

Answer 4

parameter_type[] array_name = new parameter_type[number_of_elements];

e.g.
String[] students = new String[5];

OR you can declare array elements at time of declaration:

String[] employees = {“Cloud”, “Tifa”, “Aerith”};

Question 5

Why is a string different from any other data type in Java?

Answer 5

They are not primitive data types and are instead objects.

This is how they are able to have methods attached to them, such as:

.toUpperCase()
.length()
.equals()

Question 6

What is a Headless Content Management System?

Answer 6

A backend-only CMS that makes content accessible via RESTful API’s for display on any device.

Question 7

What is feature parity?

Answer 7

Ensuring features maintain consistency / quality across multiple platforms.

E.g. Does a feature work the same on chrome and Firefox?

Question 8

What is a stateful component?

Answer 8

It is a central point that stores information in the memory about the app/component’s state. It also has the ability to change it. It is essentially a “living” thing that has knowledge of past, current and potential future state changes.

This makes it more difficult to re-use or replace in the future.

Question 9

What is a stateless component?

Answer 9

When something is “stateless”, it calculates its internal state but it never directly mutates it. This allows for complete referential transparency meaning that given the same inputs, it will always produce the same output.

This makes it easy to reuse or replace in the future.

Question 10

In database systems, what is the defintion of an atomic swap?

Answer 10

An indivisible and irriducible series of database operations such that either all occur, or none occur. It cannot be broken up. Ideal for financial transactions or trading.

Question 11

What is a GUID?

Answer 11

Globally Unique Identifier and Universally Unique Identifier

Question 12

What is a Hook in programming?

Answer 12

A place in code that allows you to tap in to a module to either provide different behavior or to react when something happens.

In a generic sense, a “hook” is something that will let you, a programmer, view and/or interact with and/or change something that’s already going on in a system/program.

Question 13

What is the difference between a data lake and a data warehouse?

Answer 13

A data lake is a vast pool of raw data, the purpose for which is not yet defined.

A data warehouse is a repository for structured, filtered data that has already been processed for a specific purpose.

Question 14

What is event sourcing?

Answer 14

Architecting the application to publish events to a event log, and allowing services to subscribe to those events for the benefits of data consistency within microservices and centralised audit logging.

Example solutions include GCP Pub / Sub and Apache Kafka.

Question 15

What is lint?

Answer 15

A static code analysis tool used to flag programming errors, bugs, stylistic errors, and suspicious constructs.

Question 16

What are the three main business benefits to utilising API’s internally within an organisation?

Answer 16

1) Cost Reduction
2) Operational Efficiency
3) Enhanced Security

Question 17

What is code rot?

Answer 17

Slow deterioration of software quality over time or its diminishing responsiveness that will eventually lead to software becoming faulty, unusable, or in need of upgrade.

Question 18

What does “this” refer to in most languages?

Answer 18

“this” binds to the object that it is being called from.

An easy way to remember what “this” will refer to is by looking at the line where the function or method is called. Whatever is to the left of the function or method will be what “this” will bind to.

https://www.youtube.com/watch?v=Pi3QC_fVaD0

Question 19

What is a constructor?

Answer 19

In class-based object-oriented programming, a constructor is used to instantiate (assign values) to each variable within the class.

Question 20

What is polymorphism in programming?

Answer 20

The use of a single interface or symbol to represent multiple different data types. For example, functions having the same names but carrying different functionalities.

A simple example: defining a constructor called “Phone” that has 3 variables “name, screenWidth, camera” and another constructor also called “Phone” with 2 variables “name, screenWidth”

Question 21

What is the keyword “Super” used for in programming?

Answer 21

It is used within Object Inheritance, to pass all the parameters that are defined within the “Super” function to the parent object and use them there instead.

Question 22

What are the four fundamental concepts of Object Oriented Programming (OOP)?

Answer 22

1) Inheritance - the procedure in which one class inherits the attributes and methods of another class.

2) Encapsulation - hides private details of a class from the outside world and only exposes functionality important for interfacing with it, such as getter and setter methods. Think of it like a API within your codebase.

3) Polymorphism - functions having the same names but carrying different functionalities.

4) Abstraction

Question 23

What is the difference between Encapsulation and Abstraction in Object Oriented Programming?

Answer 23

Encapsulation provides you with a result, but does not expose to the developer what data was used in determining that result.

Abstraction provides you with a method to call, but does not expose to the developer what logic is used under the hood.

The best way to think of this is how it is implemented within Java: Abstraction is implemented in Java using interface and abstract class while Encapsulation is implemented using private, package-private and protected access modifier

Question 24

What is the static keyword used for?

Answer 24

Static means the value of that variable belongs to the object itself, and not the instances of that object. This means that every instance of the object that has a static modifier will share that same value.

For example, all employees() may have the same static company name.

Question 25

What are the primary differences between Maven and Gradle?

Answer 25

1) Maven is defined in XML, whereas Gradle is defined programatically in Groovy.
2) This enables reusable build components for developer productivity benefit.

Question 26

How would you describe React Native to an existing React user?

Answer 26

React is used for building Web Application interfaces, and uses an additional library called React DOM to translate the React Components to the browser platform.

React Native is the alternative library to react-dom which translates React components to iOS and Android platforms. It additionally gives you access to device APIs so you can access camera, permissions etc.

Question 27

How does React Native handle JavaScript code when translating to Mobile Platforms?

Answer 27

Unlike the JSX components, the JavaScript logic is not compiled.

Instead a JavaScript thread is hosted by React Native in the native app that’s been built and JavaScript is managed and run there.

Question 28

When building React Native applications, what is the difference between Expo CLI and React Native CLI.

Answer 28

Expo CLI is the recommended option, as it is easier to get started and extrapolates more configuration effort away from the developer. It also provides more useful packages and tools that can be used when writing code.

React Native CLI places more independence on the developer, meaning there are less convenient features for build, however it does make it easier to integrate with native source code such as Java, Objective-C, Swift or Kotlin.

Question 29

What is exponential backoff?

Answer 29

Truncated exponential backoff is a standard error-handling strategy for network applications. In this approach, a client periodically retries a failed request with increasing delays between requests to ensure the service does not get overloaded.