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Java Programming for Beginners – Full Course freeCodeC Java for Beginners: Introduction In this course, Farhan Hassan Chodri, an experienced software developer, will teach you the fundamental concepts of Java. You can follow along with the whole course from within your web browser using Replit, an online IDE that supports a long list of programming languages. To get started, go to and create an account or log in if you already have one. Creating Your First Repl After logging in, click on the "Create" button to create a new Repl. Select Java from the list of languages and give your new Repl a descriptive name. Click on "Create Repl" and wait until the process finishes. Replit's default layout can be changed by going to the settings and selecting a new default layout. The default Java Repl comes with a bunch of code, including the famous "Hello World" program. To run the code, click on the "Run" button. The Hello World Program The "Hello World" program is probably the simplest executable Java program that you can write. It is important to understand each part of this program, such as the class declaration, the main method, and the output method. The program starts with a class declaration, which is a collection of related code in Java. The main method serves as the entry point to your program, and the output method prints out whatever string you pass to it as an argument. Remember that semicolons are mandatory in Java. Variables and Data Types If you want to write more complex programs, you will need to understand the different types of data and variables in Java. A variable is any entity that can take on different values. To declare a variable, you need to write the type of the variable and its name, followed by a semicolon. To define the variable, you can assign a value to it using the assignment operator. You can print out the variable to the console using the output method. Keep in mind that you cannot use an uninitialized variable in Java. You can change the value of a variable as many times as you want, but you cannot declare the same variable twice. This tutorial will cover variables, data types, and operators in Java programming. Let's start with variables. When you declare a variable in the class level, the Java compiler assigns a default value to it, which is zero for numbers. If you redeclare a variable inside a method, it will not affect the initial declaration of the variable. When naming variables, avoid single letters and use camel casing for multi-word names. There are eight primitive data types in Java, six of which deal with different types of numbers, including bytes, shorts, integers, longs, floats, and doubles. There is also a boolean data type with two possible values, true or false, and a character type that can hold any valid Unicode character. Type conversion in Java can be implicit or explicit. Implicit conversion happens when the compiler converts a smaller type of data to a larger one automatically. Explicit conversion uses the cast operator to convert a data type to another, but be careful not to lose data accidentally. Operators in Java are symbols that perform operations such as arithmetic, relational, or logical operations. There are six types of operators in Java, but only four will be discussed in this tutorial. Arithmetic operators include addition, subtraction, multiplication, division, and remainder/modulo operator. These operators work similarly to a calculator.