In this episode, we take a look at the MVC pattern. In short, MVC 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.
The lesson includes a small example, which uses the MVC pattern, so make sure to check it out.

What are Models, Views, and Controllers?

Each component has a specific responsibility and has a link to the others. That creates a solid structure for our web application.

• Model is the lowest level, responsible for maintaining the data. Each model has a connection to the database and can have relationships to other models. If any data changes, the model will notify the controller.

• The view is the only part of the app the user interacts with directly. It represents the visualization of the data that a model contains. The model never directly communicates with the view.
• A controller is the go-between for model and view. It relays data from browser to app and from app to browser. The controller receives user input, translates it to match the model, and then passes those inputs onto a view.

Using the MVC pattern correctly can help you as a developer. It ensures a smooth and easy-to-follow user experience. Although it takes time to understand how MVC works, it will pay off when creating future applications.

In the end, MVC is not hard to understand. Just keep in mind these key points:

• MVC is an architectural pattern consisting of three parts: Model, View, Controller.
• Model: handles data logic.
• View: displays the information from the model to the user.
• Controller: controls the data flow into a model object and updates the view whenever data changes.

We are happy to announce our Java Foundation Full Course! This 30-hour Java training is completely free, and it will teach you the major concepts of Java Programming! It focuses on building practical skills through 55 hands-on exercises. Keep up with the videos, and you will learn:

• Things good programmers should know (not just how to code).
• Some best practice development techniques.
• Skills in Java to use for the rest of your career.
• Master design principles, best practices, and coding conventions for writing.

Join Svetlin Nakov and George Georgiev, who are experienced programming instructors.  Svetlin helped more than 150 000 students to begin coding, learn software development and start a tech job, while George is a senior Java developer and award winner. This majestic duo will answer all your questions and problems.

All these topics are essential to your further development as a software engineer. So, make sure to solve the hands-on exercises in addition to this video. If you have no prior programming experience, just watch our programming basics course with Java. [Full Java Basics Course]

This foundation course is split into three parts. Each part covers main topics that you shouldn’t skip. We cover everything from the basics of programming to advanced features.

In our first video, you will learn:

•  Brief Introduction to Java – Java syntax, comparison operators, logical operators, loops, and debugging.
• Data Types and Variables – Learn data types, such as integers, real numbers, type conversions, Boolean, character, and string types.
•  Arrays – How to read an array from the console, process arrays, use the for-each loop, print arrays, and simple array algorithms.
• Methods – Declaring and invoking methods, parameters, values versus reference types, and method overloading.

Exercises are essential for your development as a programmer. Solve the exercises problems, in addition to this video. That is the only way to master the skill of coding.

In our second video, we will look at:

•  Lists – Reading, printing, and processing lists. You will learn how to sort lists and arrays.
•  Text Processing – Working with strings, printing, and processing text in Java.
• Associative Arrays – Maps, HashMap, Lambda functions, filtering, and processing sequences and maps.
• Objects and Classes – Private and public properties, getters, setters, constructors, etc.

Remember that programming requires patience and a lot of trial and error. As the final video goes, we will look at some essential concepts and topics.

In it, you will learn:

• Defining Classes – Constructors, Properties, and other main building blocks of every class.
• Principles of OOP – The four pillars of Object-Oriented Programming.
• Exception Handling – Exceptions, Errors, and using the “try-catch-finally” block.
• Java API Classes – Math, Random, Formatter, BigInteger, BigDecimal, and work with dates.

Earn Java Certification! After watching this course, you will be ready for the official exam from Oracle – Java Foundations 1Z0-811. This exam is also version-independent and will be valid forever.  Certification offers recognition and is proof of career growth. Become a Computer Programmer and start your career!

Learn Java from Zero to Hero! Stop waiting and start your journey today. For this course, you will solve as many as 50 coding exercises to practice your new skills.

In this lesson, you will become familiar with the Object-Relational Mapping technologies or the so-called ORMs. As a relative newcomer to programming, terms like ORMs can sound intimidating. The nice part about them is that they allow us to write code easier once we understand them.

Object-Relational Mapping technology is the idea of writing queries using your favorite programming language. We interact with a database using our language of choice instead of SQL.

Let’s say that we have an application. An ORM will convert the result of a database query into a class within our application. The selected columns will map to the class properties. On the other hand, if you push data towards the database, an ORM will map the properties of a class into columns of a table. When people say ORM, they refer to a framework that implements this technique. Here are some of the most frequently used ORM frameworks:  Entity Framework, Hibernate, Sequelize, and SQLAlchemy.

In this episode, Svetlin Nakov will explain to you what databases are.  That probably is not news to you, but the world creates a lot of data nowadays. By 2030, more than 465 exabytes of data will be created each day globally. That statistic is proof that handling data becomes essential, and that is where Databases come into the picture.

A database is 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.  For example, In a customer table, each row is a unique person, and fields like name and address describe this specific customer.

We usually say that our database is MySQL, MongoDB, SQLite, MS SQL Server, etc. That is wrong! They are not databases, but database management systems(DBMS). 

The DBMS is the software that you install on your personal computer or a server, and then you would use it to manage a database. Modern software systems use a DBMS system to manage data instead of implementing the data management internally.

One of the most important DBMS are: 

• Relational Database Management Systems (RDMS)
• NoSQL Database Systems

Today’s demo will be done with RDMSystem. They consider the relationship between the tables by using primary keys and foreign keys. Thus, it offers an advantage over other DBMS by fetching and storing the data. It is used in enterprises for storing large amounts of data.

Examples of RDBMS are:

• Microsoft SQL Server
• SQLite

The next type of DBMS  is NoSQL. Non-relational databases do not store data in tables. Instead, there are multiple ways to store data in NoSQL databases, such as Key-value, Document-based, and Column-based. Each record does not have to be in the same structure as other records. Due to this, to add additional data, you can add more records without changing the structure of the entire database. Although there are many perks to NoSQL databases, SQL databases are still more commonly used at this point.

Database systems are a necessary component of most modern software systems, and software engineers must have at least basic database skills.

In this bonus lesson, we continue with the Java Foundations Tutorial. That is the thirteenth part of this series, and if you want to see the complete list of lessons, you can do it here.

We cannot start explaining the difference between JRE and JDK without also explaining JVM. JVM or Java Virtual Machine simply helps to execute programs on our devices. It provides an environment to run the programs. JVM requires libraries and files for code execution, and these files are presented in JRE. We can have different JRE versions for different platforms. They are all platform-dependent.

JRE = set of libraries + JVM

JDK or Java Development Kit is a full-featured development kit. It has all development tool that we might require for creating java programs. JDK contains the following tools:

1. Java Runtime Environment (JRE)
2. Interpreter
3. Compiler (javac)
4. Archiver (jar)
5. Documentation generator (javadoc)

If you want to run your program you will need to use java or javac commands. The javac command is used to compile Java programs, it takes .java file as input and produces bytecode. On the other hand, the java command is used to execute the bytecode of java. It takes byte code as input and runs it and produces the output.

In conclusion, if you want to run the java or JVM-based code, then JRE is required. But if you want to develop Java and JVM-based programs, then JDK is required. Depending on your needs you will use javac and java commands.

In the current lesson, we take a closer look at the most frequently used Java API classes. Svetlin Nakov will explain all about the Math class, how to generate random numbers, the need for BigInteger and BigDecimal in programming, and how to work with date and time in Java. We will also look at two of the main Java classes – Arrays and Formatter.

The Math class contains methods for performing basic numeric operations, such as round, min, max, abs, ceil, etc.. The Arrays class contains various methods which facilitate array manipulation. String.format() allows us to return the formatted string by given locale, format, and arguments.

In this lesson you will find many helpful examples and exercises, so make sure to practice what you’ve learned! That’s the only way to grasp the concept at hand.

BigInteger and BigDecimal are used for handling large and small numbers with great precision. BigInteger will throw an exception when the result is out of range. BigDecimal gives the user complete control over the rounding behavior. 

Importing a single package allows us to work with the date and time API.
In this lesson you will find many helpful examples and exercises, so make sure to practice what you’ve learned! 

As always, we advise you to pause the video right before the solving part of each problem and try to do the exercises on your own first. Then, if you have difficulties, just watch the provided solutions in the video. If you still have questions, we’re always here to help! 

*The exercise descriptions are to be found in the PDF document at the end of this post.

In this episode, we’ll focus on modern mobile app development, while using React Native. 

In the previous episode, we reviewed “React“ which is the number one web framework for 2021. Today we will be focusing on modern mobile app development technologies and React Native. 

The lesson includes a small demo React Native mobile app, which defines a JSX component and renders it in the Web browser. 

For front-end and client-side app development, mobile apps are important. To build our mobile application we need to combine development principles, concepts, platforms, technologies, frameworks, libraries, and tools. In this lesson, we will be reviewing the two major mobile app platforms that dominate the markets.

 

They are Android and ioS. Each one of them has its perks: 

• Android devices are less expensive compared to iOS devices. They also provide more freedom and options for developers. 
• iOS devices are slightly less popular, despite their high price. This market is more profitable because most apps follow a paid model. 

Mobile app development technologies are split into several categories: Android, iOS, and Hybrid. We have talked about the first two, but what are Hybrid technologies? They are based on JavaScript and HTML5 using an embedded Web browser. There are more mobile app dev technologies, but those are the well-known ones we will be talking about. 

In the current lesson, we will review a highly popular JavaScript UI library, called “React“. In short, React.JS is a component-based front-end technology for the Web. The JSX components in React combine HTML and JavaScript to display the component UI, which is bound to the internal component state.

The lesson includes a small demo React app, which defines a JSX component and renders it in the Web browser.

Later in the lesson, you will find a slightly more complicated demo: how to create a simple React calculator, which sums two numbers. We will review each of the files inside the sample React app to understand better how it works internally.

So, what is React?

When we talk about user interface and front-end frameworks, it is worth mentioning React.

• React is a powerful JavaScript library from Facebook for building Web user interfaces using HTML, CSS, and JavaScript. The UI is built from JSX components, which combine HTML + JavaScript using a built-in templating engine.
• React is а component-based UI library.
• With React, developers create reusable UI components, which have a lifecycle, internal state and behavior.

It is discussable whether React is a library or a framework. It is maybe somewhere in between.

By adding some additional components like React Router, MobX, Redux, Flux, React Toolbox, and some others, we can turn to React into a fully-functional Web front-end framework.

In this episode, you’ll learn how to create a desktop application using Windows Forms and C#.  
We will take a closer look at how GUI frameworks work with a live code example.

In programming, GUI means “graphical user interface“, which is a system to interact visually with the users through UI controls, such as forms, buttons, text boxes, and others.
In this session, we will show you a sample desktop app based on the Windows Forms GUI framework. We will build a simple calculator, which sums two numbers.

We will get familiar with the structure and the front-end part of the app: the main form, holding the UI controls. We will look at how the app is built, by extending a class from the UI framework, from a composition of components, and how event handlers are called from the framework to respond to user interactions.

The demo code is designed to run in a Windows environment, using Visual Studio and the .NET Framework. It can’t run on Mac or Linux. Sorry, this is a limitation of the Windows Forms technology.

In this episode, we’ll be talking about UI and component libraries that provide ready-to-use UI controls and program components, and software frameworks that provide a technical foundation for developing certain types of apps. Both libraries and frameworks speed-up software development and are used every day by millions of developers, so you as a developer, should understand these concepts very well.

 

In this session we will explain the main difference between a library and a framework, which in short is the following:

• Libraries extend your app by plugging a software component in it. They use the traditional program flow.
• Frameworks are foundations of functionality, which developers extend to build an app. They use the “inversion of control” program flow.

Finally, we will explain the concept of “inversion of control” (IoC) and its purpose in modern software development. Svetlin Nakov will give you an example of how UI frameworks take the program execution flow and call your code through events when the user interacts with the user interface. This is an “inverted” program flow – IoC.

In the current lesson, we take a close look at exception handling and why it’s important in software engineering.

What are exceptions? We’ve all seen one, there is no way to write completely bug-free code. In short an exception is a problem that arises during the execution of the program. 

Exceptions simplify code construction and maintenance and allow problematic situations to be processed at multiple levels.

In Java exceptions are objects. The base for all exceptions is the Throwable class – it contains information about the cause of the exception, its description, and the stack trace.

There are two types of exceptions – checked (also known as compile-time exceptions), and unchecked (also known as runtime exceptions).

Exceptions can be handled by the try-catch construction. The try-finally block is also used, especially when we want to ensure the execution of a given block of code. 

To raise an exception, we use the throw keyword. When an exception is thrown the program execution stops, and the execution travels over the stack until a matching catch block is reached to handle it. 

In this lesson you will find many helpful examples and exercises, so make sure to practice what you’ve learned! That’s the only way to grasp the concept at hand.

In this video you will become familiar with the topic of “routing“, used for navigation in modern app development. In short, routing is the technology used to switch between different UI views (different app screens), based on changes of the current URL in the navigation bar. Routing is typically implemented through a routing library.

In this lesson, we will see how routing works in front-end apps. We will show you a sample routing library, which changes the view on the front-end, when the browser navigates to certain URL. Finally, we will demonstrate the concept of routing with a live coding example in JavaScript, so that we see how everything is done.