In this lesson, we take a look at Back-End technologies in software development. That is a technical term that deals with server-side operations, including CRUD functions with database and server logic. Meanwhile, Front-End development is programming which focuses on the visual elements of a website or app that a user will interact with.

Back-End technologies are essential in the development of software projects. Whether you are a startup founder, or a corporate decision-maker, selecting the right Back-End technology is crucial to determine your project success. Choosing the correct Back-End technologies can guarantee scalability, functioning speed, and instant response to customers’ needs.

In our video, we explain foundation concepts that aspiring developers shouldn’t miss. Keep up with the videos, and you will learn about:

• Databases: They are a place for storing our data but in an organized structure.  Data is organized and stored in the form of tables. A table contains rows and columns. Each row in a table is a record, and column a field that describes the row.  Read our article about them here.

• ORM: This is short of Object Relational Mapping. It is the idea of writing queries using your favorite programming language. You interact with a database using your language of choice instead of SQL. Read our article about them here.

• MVC: The term stands for Model–View–Controller. It is a design pattern used to help us build frameworks for applications. The MVC splits the application into three different sections. Each section represents one word from the abbreviature. Each component has a specific responsibility and has a link to the others. Read our article about them here.
• Web Services and APIs:  Web Service is a network-based resource that fulfills a specific task. On the other hand, API is an interface that allows you to build on the data and functionality of another application. There is an overlap between the two. WEB services are APIs, but APIs can be offline. Many public APIs are transparent, with open documentation and self-service portals for quick developer onboarding. On the other hand, Web Services are not open source. Instead, they tend to offer specific data and functionality to partners.

• REST and RESTful Services: REST is a set of architectural constraints, not a protocol or a standard. API developers can implement REST in a variety of ways. When a client request is made via a RESTful API, it transfers a representation of the state of the resource to the requester or endpoint. This information, or representation, is delivered in one of several formats via HTTP. Restful Web Services is a lightweight, maintainable, and scalable service built on the REST architecture. It also exposes API from your application in a stateless manner to the calling client. The calling client can perform predefined operations using the Restful service.

• Virtualization, Containers, and Docker: Virtualization is a relatively new technology that allows creating a completely isolated machine from scratch, all in software. Nowadays, companies are starting to prefer Docker. It s a tool that uses containers to make the creation, deployment, and running of applications a lot easier. Read our article about them here.

Hopefully, reading all this about Back-end technologies will help you in making the right decision. No matter what language you are using, all of those concepts are the same. For every aspiring programmer, it’s a must to know all of the topics. If you want to learn more about the differences between Front-End, Back-End, and Full-Stack technologies you can read our article here.

In this episode, we take a look at Operating Systems. In short, Operating System(OS) is the connection between users and computer hardware.

Simply put, you give instructions to a computer, which the Operating System does. OS is software that manages the computer hardware by hiding hardware complexity, managing computational resources, and providing isolation and protection. Most importantly, it directly has privileged access to the underlying hardware. Major components of an OS are the file system, scheduler, and device driver.

Different Operating Systems run on different types of hardware and are designed for different types of applications. For example, iOS is designed for iPhones and iPad tablets, while Mac desktops and laptops use macOS. Your computer or smartphone comes equipped with an OS, but you can install another one in some cases. For Software developers, Linux is one of the must-learn Operating Systems.

Users, who are new to Linux, usually discard it by falsely considering it as a difficult and technical OS to operate but, to state the truth, in the last few years Linux, Operating Systems have become a lot more user-friendly than their counterparts like Windows, so trying them is the best way to know whether Linux suits you or not. There are thousands of Linux-based Operating Systems that offer state-of-the-art security and applications.

If you still think that Linux OS is not worth it, let’s see its advantages over other Operating Systems.

• It’s 100% free.
• It’s easy to install.
• The consumption of resources and space is small, unlike Windows.
• There is community support for troubleshooting.
• Every program like Photoshop, Microsoft Word has an alternative, free version.
• Linux has powerful command prompts
• It works virtually on any modern era computer.

If you want to try Linux without changing your Operating System, you can read our previous article about Virtualization here.

An Operating System is the fuel required to run your computer at your convenience. There are many OS out there that make it possible. Choose the best Operating System that suits your needs and comfort.
Whatever you choose, you won’t be making a mistake as long as you are satisfied with it.

In this lesson, you will become familiar with: virtualization, containers, docker, and cloud platforms.
Have you ever wondered how to operate multiple Operating Systems on your computer? Thanks to virtualization, we can do that!

Virtualization is a relatively new technology that allows creating a completely isolated machine from scratch, all in software. Its dictionary definition is creating a virtual instance of an operating system, server, storage device, etc. In the IT industry, virtualization is running a virtual instance of a computer as a layer abstracted from the actual hardware.

World-famous providers like Linux and other open-source cloud solutions define virtualization as a technology that lets you create IT services using resources traditionally bound to hardware. It allows you to use a physical machine’s full capacity by distributing its capabilities among many users or environments”.

Nowadays, companies are starting to prefer Docker. It s a tool that uses containers to make the creation, deployment, and running of applications a lot easier. It binds the application and its dependencies inside a container.

But what is the difference between Docker and virtual machines?

Docker is an example of virtualization, but with a few differences:

• Containers share the same system resources and don’t have separated resources.
• A Docker doesn’t have an OS inside.
• It allows running multiple workloads on the same OS.

For example, if you have a 1 GB container image and want to use more than one virtual machine, you need to have 1 Gb multiplied by the numbers of the VM you want. If you use Docker, you can share the 1 GB between all the Docker containers.

In most real-life cases, your applications will have external dependencies, such as databases, message queues, or other external services that your application communicates to. You will need a reliable and easy-to-use way of bringing these dependencies into your development environment. Docker has a good solution for this called Docker Composer. It’s a tool for defining and running multi-container applications. That, combined with a cloud platform, will be the perfect solution.

A cloud platform is the operating and hardware system in a remote internet-based data center. It allows software and hardware products to co-exist remotely and at scale.

Overall, Virtual Machines are the most effective way to reduce IT expenses while boosting efficiency and agility for all-size businesses. Docker allows applications to be packaged with all the dependencies inside, which simplifies the deployment process quite a bit, and you get to have full reproducible environments.

A nested loop is the placement of a loop inside another loop to execute the operations that need multiple loop traversals, such as printing star patterns. Although it helps to make our task easier, it also increases the complexity of the program thus must be used efficiently.

Now, onto the important part: if a loop exists inside the body of another loop, it is called a nested loop. It has no limitations that only similar types of loops can be nested.

We can nest any loop inside any other loop, such as while loop inside for loop, and all different combinations are accepted.

In the chart, first, when we enter the body of the program, a statement such as initialization gets executed. Once a loop is found, the program checks for the condition for the outer loop, and if it returns true, it enters the loop. Once it enters the outer loop and encounters the inner loop, variables are initialized if any are present. Then it checks the condition for the inner loop, and if it returns true, the program enters into the inner loop. This procedure is repeated several times, and then the program exits from the second loop, then the first loop, and move to statements present after the loop.

A While Loop is a control flow statement that allows code to be executed repeatedly based on a given boolean condition. The While Loop can be thought of as a repeating if statement.

In the expression, we have to test the condition. If the condition evaluates to true, then we will execute the body of the loop and go to update the expression. After executing the loop body, this expression increments/decrements the loop variable by some value. Otherwise, we will exit from the While Loop.

How does While Loop execute?

1. Control falls into the While Loop.
2. The flow jumps to the condition
3. The condition is tested.
   1. If it is true, the flow goes into the body.
   2. If it is false, the flow goes outside the loop
4. The statements inside the body of the loop get executed.
5. The update takes place.
6. Control flows back to Step 2.

One more thing, which we have already read in the previous article about advanced conditional statements, is the break statement. It ends the loop immediately when it is encountered. The break statement is usually used with a conditional statement inside the loop.

Both While and For Loops repeat a block of code. We use For Loops when we preliminary know the number of iterations. If we don’t know when the exit condition will be met, we use While Loops.

In programming, a loop is used to repeat a block of code until a specified condition is met. The For Loop is best when you want to do something for a fixed number of times.

How does For Loop work?

1. Control falls into the For Loop. Initialization is done.
2. The flow jumps to the Condition.
3. The Condition is tested.
   1. If it is true, the flow goes into the body.
   2. If it is false, the flow goes outside the loop.
4. The statements inside the body of the loop get executed.
5. The update takes place, and the flow goes to Step 3 again.
6. The For Loop has ended, and the flow has gone outside.

This process goes on until the test expression is false. When the test expression is false, the loop terminates.

Say we want to loop over a range of numbers and print out each one along the way. We can do this best with a For Loop. We will start from the first number, print it out, move to the next number to do the same thing, and continue until we’ve printed each number. Let’s print the numbers zero through nine:

Let’s look at the first line of the For Loop and the three parts necessary to make it work. First, we have an initialization expression, then termination expression, and increment expression in the end.

The initialization expression initializes the loop and is only executed once when the loop starts. That is where you must declare and initialize a variable, usually of type int, to hold an initial number that will be used to loop until it reaches a specific value. That can be thought of as the start of the range to iterate over. In our case, we started at 0.

The For Loop will continue looping until the termination expression evaluates to false. The termination expression is evaluated before each iteration of the loop, and it must return a boolean to decide whether or not to continue looping. If the boolean returned is equal to true, we will run the body of our For Loop again. In our case, the loop terminates after it prints 9.

The increment expression is executed after each iteration of the loop. To increment the variable, we initialize it by using the ++ operator. That allows the termination expression to know how many times the loop loops. The initialization variable count, in our example, starts at 0, and it’s printed out. Then the incrementer increments it, and the next iteration of the loop runs to print the new value and continues that way until it prints 9.

In conclusion, you should use a For Loop when you know how many times the loop should run. There are other more advanced iteration structures that we will look at in the next article.

There may be a situation when you want to check for another condition after a condition resolves to true. In such a situation, you can use nested conditional statements. In them, you can have a statement inside another statement and so on.

A Switch Statement is usually more efficient than a set of nested ifs. When we have to choose which one to use, it’s based on readability and the expression that the statement is testing. We use a switch statement to test the value of a variable against a list of case values, while we use an if-else statement for taking a decision.

If-else statement evaluates integer, character, pointer, floating-point type, or boolean type. On the other hand, the switch statement evaluates only character or an integer datatype. It’s known to be hard to edit if-else statements since it’s tedious to trace where the correction is required. Many people agree that it’s much simpler to correct switch statements since they’re easy to trace.

There can be any number of case statements within a switch statement. Each case is followed by the value to be compared to and after that a colon. When the variable being switched on is equal to a case, the statements following that case will execute until a break statement is reached. If that happens, the switch terminates, and the flow of control jumps to the next line following the switch statement. Not every case needs to contain a break. If no break appears, the flow of control will fall through until a break is reached. all the case statements will get executed as soon as the compiler finds a comparison to be true.

A switch statement can have an optional default case, which must appear at the end of the switch. The default case can be used to perform a task when none of the cases are true. No break is needed in the default case. The  switch statement works much faster than an equivalent if-else statement. During execution, instead of checking which case is matching, it only decides which case has to execute. It’s more readable compared to if-else statements.

A conditional statement is a piece of code that checks the given condition, and when it is true, the code related to it is performed. It is used to make decisions based on the conditions. Conditional statements execute when there is no condition around the statements. If you put a condition for a block of statements, the execution flow may change based on the result evaluated by the condition. This process is called decision-making.

Conditional statements begin with the keyword if followed by parentheses. An expression is placed inside the parentheses, then evaluated when the conditional statement is reached. 

The parentheses are followed by a block, which is defined inside opening { and closing } curly brackets. The source code inside the block executes if the expression inside the parentheses evaluates to true. If the expression in the conditional statement evaluates to true, the execution of the program progresses to the block defined by the conditional statement.

On the other hand, if the expression evaluates to false, the execution moves on to the statement after the closing curly bracket of the current conditional statement. Using the else command, we create an alternative option for when the conditional expression evaluates to false. In the case of multiple conditions, we can use the else if  command. else if is like else, but with an additional condition. It follows the if-condition, and they may be multiple.

To sum it up, conditional statements are something that you must learn if you want to continue developing as a programmer. They s are specified by a set of statements having boolean expressions which, are evaluated to a boolean value true or false. Conditional statements help us to make a decision based on certain conditions.

Data types specify the different sizes and values stored in a variable. There are two types of data in Java:

• Primitive data types
• Non-primitive data types

To start, we will be using these data types only:

• int –  holds a wide range of non-fractional number values.
• double – only takes up to 8 bits of memory
• boolean – can contain only two values: true or false.
• char – is a symbol representing a Unicode-encoded character.
• String – is a sequence of characters

Besides printing them on the console, we can use them for various arithmetic operations. The table on the right shows different types of arithmetic operations. All of them are the same as the arithmetic operations you have learned in school.

These may seem like simple operators, but when correctly, used they can be of help on more complex projects.