Getting Started with Java

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

What is Java?

Unlike languages such as JavaScript (which is interpreted), Java is a compiled language. This means the code you write is translated into an intermediate format called bytecode, which the Java Virtual Machine (JVM) then runs 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 many types of projects.
• Active community: Thousands of libraries and plenty of support available.

The first Java program

public class MyProgram {
    public static void main(String[] args) {
        System.out.println("Hello, world!");
    }
}

What did we just do?

1. public class MyProgram: Defines a public class called MyProgram.
2. public static void main(String[] args): The program entry point. It is the first thing that runs.
3. System.out.println("Hello, world!"): Prints the text to the console and moves to the next line.

Standard output

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

• System.out.println(): Prints and adds a newline.
• System.out.print(): Prints without adding a newline.
• System.out.printf(): Lets you print with formatting (like in C).
• System.out.write(): Writes a single character (less common).

printf example:

String name = "Juan";
int age = 25;
System.out.printf("Name: %s, Age: %d\n", name, age);