# 1.1 Your First Java Program

The classic first program when introducing any new language is **Hello World**, or a program that prints `Hello World` to the console. In Java, **Hello World** can be written as such:

```java
void main() {
    IO.println("Hello world!");
}
```

Compare this with the Python equivalent:

```python
print("hello world!")
```

Compared to the extreme simplicity of Python, we observe the following features of this simplest Java program:

* The **`main`** function: all the code that runs must be inside of a function called main. We'll cover what the `void` means later.
* **Curly braces** `{}` enclose sections of code (functions, classes, and other types of code that will be covered in future chapters).
* All statements must end with a **semi-colon**.
* Printing requires us to use dot notation, going to some library called `IO` and asking for its print function.

For fun, see [Hello world! in other languages](https://www.rosettacode.org/wiki/Hello_world/Text).
