Getting Started with Java

Java is a powerful, versatile general-purpose programming language. It is used in everything from mobile applications (Android) to large enterprise systems and servers.

What is Java?

Unlike languages like JavaScript (which is interpreted), Java is a compiled language. This means the code you write is translated into an intermediate format called Bytecode, which is then executed by the Java Virtual Machine (JVM) on any platform.

The advantages of learning Java

  • High job demand: It is one of the most widely used languages in the industry.
  • Portability: “Write once, run anywhere”.
  • Flexibility: It adapts to multiple types of projects.
  • Active community: Thousands of libraries and available support.

The first Java program

public class MiPrograma {
    public static void main(String[] args) {
        System.out.println("¡Hola, mundo!");
    }
}

What did we just do?

  1. public class MiPrograma: Defines a public class called MiPrograma.
  2. public static void main(String[] args): The program’s entry point. It is the first thing that runs.
  3. System.out.println("¡Hola, mundo!"): Prints the text to the console and jumps to the next line.

Standard output

In Java we use the System.out class to display information:

  • System.out.println(): Prints and jumps to a new line.
  • System.out.print(): Prints without jumping to a new line.
  • System.out.printf(): Allows printing with formatting (like in C).
  • System.out.write(): Writes a single character (less common).

Example of printf:

String nombre = "Juan";
int edad = 25;
System.out.printf("Nombre: %s, Edad: %d
", nombre, edad);