App Dev Domain

Question 1

I: “ERROR ESTABLISHING CONNECTION TO DATABASE”

Answer 1

Check Database Connection Credentials

Ping the DB from the Application server through the port on which the DB was configured

Check Application logs

Possible Authentication issue

Possible DB maintenance

Check if the connection pool is up and running

Look at more granular stuff - is the driver working - not corrupt

Question 2

I: WEB APPLICATION FRAMEWORKS

Answer 2

Ruby on Rails
Django
Angular
ASP.NET

Question 3

I: JSON

Answer 3

JSON is JavaScript Object Notation. Its format is often used for serializing and transmitting structured data over a network connection.

Question 4

I: SCRIPTED LANGUAGE

Answer 4

A scripting language is a programming language for a runtime system that automates the execution of tasks. Scripting languages are usually interpreted at runtime rather than compiled.

• Perl
• PHP
• Python
• Ruby

Question 5

I: COMPILER

Answer 5

Compiler is a software program that transforms high-level source code into a low-level object code in a machine language, which can be understood by the processor.

Question 6

I: FUNCTIONS

Answer 6

is used when a value is returned to the calling routine

Question 7

I: DEADLOCKS

Answer 7

Deadlock occurs when the waiting process is still holding on to another resource that the first needs before it can finish.

Question 8

I: LOOSELY COUPLED ARCHITECTURE

Answer 8

Loosely coupled architectures (aka Microservices) are lean, with a single responsibility, without many dependencies, allowing teams to work independent, deploy independent, fail and scale independent, increasing business responsiveness.

Question 9

I: DISTRIBUTED and SCALABLE SYSTEM

Answer 9

Avoid the single point of failure.

Scale horizontally, not vertically.

View your application as a service with an API first.

Cache everything, always.

Design for maintenance and automation.

Strive for statelessness.

Be prepared for failure.

Question 10

I: THREAD POOL

Answer 10

is a software design pattern for achieving concurrency of execution in a computer program.

Question 11

I: SOAP

Answer 11

SOAP (Simple Object Access Protocol) is a message protocol that allows distributed elements of an application to communicate. It is an integral part of the service-oriented architecture (SOA) and the Web services specifications associated with SOA.

Question 12

I: OPTIMIZE CODE

Answer 12

Use a Profiler

Compiler Optimizations

Tuning the Code

Collect common subexpressions.

Replace expensive operations by Cheap ones.

Eliminate Loops

Cache frequently used values

Rewrite in a lower-level language

Include Code Inspection into your Governance Models

Question 13

I: QUEUES

Answer 13

A queue is like a buffer. You can put messages into a queue, and you can retrieve messages from a queue.

Redis 
RabbitMQ
ActiveMQ 
Amazon MQ
Amazon SQS

Question 14

I: PUBLISH SUBSCRIBE PATTERN

Answer 14

its where publishers do not program the messages to be sent directly to specific receivers, called subscribers, but instead categorize published messages into classes without knowledge of which subscribers, if any, there may be.

Question 15

I: REST

Answer 15

is where server-side data are made available through representations of data in simple formats.

This format is usually JSON or XML but could be anything.

Question 16

I: YAML

Answer 16

is a human-readable data-serialization language. It is commonly used for configuration files and in applications where data is being stored or transmitted.

Question 17

I: XML

Answer 17

XML is a markup language that defines a set of rules for encoding documents in a format that is both human-readable and machine-readable

Question 18

I: COMPILED LANGUAGES

Answer 18

Compiled Languages computers do not actually understand the code we write. We need to translate our human-readable code to machine-readable code.

• C
• C++
• Java

Question 19

I: INTERPRETED LANGUAGES

Answer 19

Interpreted Languages interpreters will run through a program line by line and execute each command.

• PHP
• Ruby
• Python
• JavaScript.

Question 20

I: OBJECT-ORIENTED PROGRAMMING

Answer 20

Object-oriented programming (OOP) refers to a type of computer programming (software design) in which programmers define not only the data type of a data structure, but also the types of operations (functions) that can be applied to the data structure.

Question 21

I: RPC

Answer 21

RPC is the earliest, simplest form of API interaction. It is about executing a block of code on another server, and when implemented in HTTP or AMQP it can become a Web API.

Question 22

I: SUBROUTINES

Answer 22

is used when a desired task is needed, but no value is returned.