Lessons

In this lecture you will get to grips with Java’s numeric and character types: what integral and floating-point types exist, why BigInteger and BigDecimal are useful, how to use suffixes and underscores in literals, what char is and how it relates to Unicode. Practical tables, examples, and tips — all in one place.

In this Java lecture, you will understand what floating-point numbers are, how the float and double types differ, how to declare and initialize variables, read input via Scanner, format output using String.format, and also see common mistakes when mixing int and double in calculations.

Why in Java the expression 0.1 + 0.2 does not give exactly 0.3, how to correctly compare floating-point numbers using a tolerance, which special values double has ( Infinity, NaN) and how to check them using Double.isInfinite and Double.isNaN. We break down typical mistakes and show practical examples.

In this lecture we will cover how to round and nicely display numbers in Java: the Math.round() method, the variants Math.floor(), Math.ceil(), Math.rint(), rounding to the required number of digits, formatting with DecimalFormat and String.format, as well as the difference between rounding and formatting and common mistakes. All with practical examples and tables.

We break down type conversions in Java: automatic (widening) and explicit (narrowing) casts between int, double, long, byte, char, rules for mixed expressions, transitions between numbers and strings using Integer.parseInt and Integer.toString, and how a cast ( ( int )) differs from rounding via Math.round. With practical examples and typical mistakes.

In this lecture, you will learn how the process of developing an IT product is organised: what roles exist on the team, how they interact, what Product Owner, UX Designer, DevOps, and developers do, and you will also get acquainted with the history of approaches to building modern digital services.

In this motivational article, you will learn why the path to success is unique for everyone, how to choose your own strategy without sacrificing important things, and why it’s important not only to work hard but also to work smart. This material will help you look at competition, hard work, and cultural attitudes from a new angle.

In this lecture, we’ll get acquainted with arrays in Java: what this container object is, how to create arrays of different types, access cells by index, understand how arrays are stored in memory, use the length property, and avoid common mistakes like going out of bounds. Everything is backed by code examples and clear illustrations.

In this lecture, we go over everyday operations with one-dimensional arrays in Java: arrays of type String, the value null and its pitfalls, quick initialization techniques, the for-each loop, modifying elements, basic computations (sum, maximum, minimum, average), input/output, and typical mistakes. All with clear code examples and explanations.

In this lecture, we cover two-dimensional arrays in Java: the declaration syntax int[][], creation and initialization, accessing elements by indices [row][column], filling and printing tables. We’ll see why these are “arrays of arrays” and why this model is convenient in practice. With examples and illustrations.

In this lecture we dive into jagged arrays in Java: how they differ from “classic” two-dimensional ones, how to declare and initialize them ( int[][], new int[ 3][]), how to iterate using regular and for-each loops, and we create examples with student grades. Additionally, we will look at multidimensional arrays ( int[][][]) and common mistakes: ArrayIndexOutOfBoundsException, NullPointerException, and confusion with length.

Digging into Java’s utility class Arrays: how to quickly sort and fill arrays, copy whole arrays and ranges, correctly compare contents ( equals/ deepEquals), and pretty-print data ( toString/ deepToString). Lots of practical examples, nuances of half-open ranges, and common pitfalls.