Free Programming Courses

Java Course: Learn Java Programming from Scratch

Learning programming is a challenging and lengthy journey. Understanding a language’s syntax is just the first and easiest step, without which you cannot start practicing. This course will introduce you to the basics of writing Java programs, laying a solid foundation for further development of meaningful and functional applications.

Java Basics

1. Hello, World!

2. Comments

3. Statements

4. Syntax Errors

We will learn Java from scratch, starting with the very basics. The first module serves as a foundation for writing meaningful programs. Here, we will discuss how to write your first Java code, explain what comments are and why they are needed, and explore testing by reviewing how to check your solutions and interpret test results.

Arithmetic

5. Arithmetic Operations

6. Operators

7. Commutative Operation

8. Composition of Operations

9. Operator Precedence

10. Floating-Point Numbers

11. Linter

Modern software is designed to serve businesses, assist in daily life, and provide entertainment. However, at their core, computations remain fundamental. The simplest and most fundamental topic in programming is arithmetic. In this module, we will translate arithmetic operations into programming language, recall school-level math rules, and discuss operator precedence.

Strings

12. Quotes

13. Escape Sequences

14. Concatenation

Text in programming is called “strings,” and this topic is more complex than it may seem. How do you print a phrase that contains both single and double quotes? How do computers handle text when they know nothing about letters? This module covers various aspects of working with text, from quotes and escaping to encoding.

Variables

15. What is a Variable?

16. Modifying a Variable

17. Choosing Variable Names

18. Errors in Working with Variables

19. Expressions in Definitions

20. Variables and Concatenation

21. Naming Variables

22. Magic Numbers

23. Constants

Information can be stored in special “containers” called variables. This allows for the reuse of existing data without duplication in different parts of the code. In this module, we will discuss how to modify and name variables to make your code understandable for any developer. You’ll realize that naming a variable isn’t as easy as it seems! We’ll also show you how to use variables to simplify complex calculations.

Java Data Types

24. Why Do We Need Data Types?

25. Explicit Typing

26. Types of Data

27. The null Value

28. Explicit Type Conversion

Java is a language with strict static typing. How does this affect your code? What are data types, what kinds exist, and who determines them? This module will answer these questions.

Method Calls

29. Methods and Their Invocation

30. Method Parameters

31. Method Invocation as an Expression

32. String Immutability

33. Method Call Chains

34. Determinism

35. Standard Library

36. Types of Methods

In programming, any arbitrary operation is expressed through “functions.” Functions are the building blocks that programmers use to create systems. In Java, functions are called methods. In this module, we will learn how to use existing methods, examine method signatures in documentation, and understand how to use them.

Defining Methods

37. Creating (Defining) a Method

38. The main Method

39. Returning Values

40. Defining Methods

41. Optional Method Parameters

Defining your own methods significantly simplifies programming and maintenance. The ability to define methods allows you to combine complex operations into a single unit, hiding all complexity inside a simple method. By learning to create methods, you will take the first step toward building truly useful programs—and we will guide you through it. In this module, you will create your first method and learn to give it (and variables) meaningful names.

Logic

42. Boolean Typehod

43. String Comparison

44. Combining Operations and Methods

45. Logical Operators

46. Negation

Logical expressions help answer questions that arise during a program’s execution. Is the user authenticated? Is the subscription paid? Is the year a leap year? In this module, we will study predicate functions—functions that ask a question and return an answer: true or false. We will practice writing such functions and move on to more complex logical expressions.

Conditional Statements

47. If Statement

48. If-Else Statement

49. Else-If Statement

50. Ternary Operator

51. Switch Statement

A predicate function answers a question, but usually, that’s not enough—we need to execute a certain action based on the answer. If and Switch are Java constructs that allow a programmer to choose how a program behaves under different conditions: skipping some instructions and executing others. In this module, we will practice using them.

Loops

52. While Loop

53. Data Aggregation (Numbers)

54. Data Aggregation (Strings)

55. Iterating Over Strings

56. Conditions Inside Loops

57. String Formation in Loops

58. Syntactic Sugar

59. Increment and Decrement

60. Breaking Out of Loops

61. For Loop

Any code can be repeated tens, thousands, or even millions of times. When combined with other known tools—variables and conditions—loops open up many possibilities for building programs and complex systems. Here’s a simple example: imagine you need to find a specific phrase in a 500-page textbook. You remember the phrase but not the page number. The simplest (and longest) way would be to go through each page sequentially until you find it. Loops exist to handle such repetitive actions efficiently.