Lessons

In this lecture you will learn how the programmer’s career ladder is structured, how modern developers differ from the “coders” of the past, why it is now more important to assemble solutions from ready-made components rather than write everything from scratch, and how the Java Software Engineer profession has transformed in the era of the cloud and DevOps.

In this article, you will learn why programming is accessible to everyone, what advantages the profession of a programmer offers, how CodeGym’s innovative approach to learning is different, and why practice matters more than theory. The material will inspire you to believe in yourself and start your path in IT!

In this lecture, we’ll break down the basic structure of a Java program: what classes and fields are, how the entry point main() works, why the access modifiers public/ private and the static keyword are needed, what the short form of main() in Java 21 is, and a small tip for IntelliJ IDEA.

We break down how to declare and call methods in Java: the general form, examples with and without parameters, the difference between parameters and arguments, hands-on practice with small utility methods, and careful use of static for calling from main. In the end — common mistakes and how to avoid them.

In this lecture, we cover why methods in Java need return values, how to choose the result type, how the return statement works, where and how to use the returned result, as well as nuances of early termination in void methods and common mistakes. Practice includes examples with int, double, String, and boolean.

In this lecture, we break down how method parameters work in Java: why people say that in Java it is always by value, how primitives ( int, double, boolean) differ from reference types (arrays and objects), why changing array elements inside a method is visible from the outside, while assigning a new reference is not. Clear examples, typical mistakes, and practical takeaways are provided.

In this lecture, we’ll look at access modifiers in Java — public, private, and package-private visibility (no modifier) — as well as variable scopes: local, parameters, and class fields. We’ll understand what variable shadowing is and how to access fields via this and via the class name. At the end, we’ll cover common mistakes and how to avoid them.

In this lecture, you’ll learn how modern IT products are really created: why development is constant change, how the release process works, why only code running in production brings value, and what stages your code goes through from being written to delivering value for users. All with examples, analogies, and real stories from the industry.

In this article, you will learn how the emergence of the internet and the development of the IT industry changed the world, why professions in information technology are in demand, what prospects open up for IT professionals, and why IT specialists can work and live anywhere. We will also look at the advantages of the profession and opportunities for immigration.

In this lecture we’ll cover how to escape special characters in Java strings, use line breaks and multi-line text blocks """, work with Unicode (including surrogate pairs) and emoji, and also which mistakes occur most often when printing quotes and file paths. All with clear examples.

In this lecture, we’ll break down how to neatly and reliably compose text with data in Java: from simple concatenation with the + operator to the powerful String.format() formatter. Through examples, we’ll look at format specifiers ( %s, %d, %.2f, %n), alignment, percentages, and—briefly—date/time and locales. We’ll finish with practice and a review of common mistakes.

In this Java lecture, we break down the most useful methods of the String class: how to get the length of a string with length(), extract substrings via substring(), search text with indexOf() and lastIndexOf(), get characters using charAt(), convert a string to a character array with toCharArray(), replace fragments using replace(), and trim the edges of a string with trim() and strip(). At the end — practical exercises and a breakdown of common mistakes.