In the previous tutorial you learned how to install Java on your computer. Now, let's write a simple Java program.
The following program displays Hello, World! on the screen.
public class Main {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
Output
Hello World!
Note: A Hello World program is used to introduce a new programming language. It is the first program that every beginner writes.
It's okay if you don't understand how the program works. We will learn all about them in upcoming tutorials. For now, just write the exact program and run it.
Working of Java Program
Congratulations on writing your first Java program. Now, let's see how the program works.
public class Main {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}
Notice the following line of code:
System.out.println("Hello, World!");
In the above code, the System.out.println() statement prints the text Hello, World! to the screen.
Remember these important things about printf:
- Everything you want to print should be kept inside parentheses
(). - The text to be printed is enclosed within double quotes
"". - Each
System.out.println()statement ends with a semicolon;.
Not following the above rules will result in errors and your code will not run successfully.
Basic Structure of a Java Program
As we have seen from the last example, a Java program requires a lot of lines even for a simple program.
For now, just remember every Java program we write will follow this structure.
class Main {
public static void main(String[] args) {
...
}
}
We will write our code in place of ... inside curly braces.
Next, we will be learning about Java comments.