<p>I would like to determine the operating system of the host that my Java program is running programmatically (for example: I would like to be able to load different properties based on whether I am on a Windows or Unix platform). What is the safest way to do this with 100% reliability?</p>

You can use:
```
```
System.getProperty("os.name")
```
```
P.S. You may find this code useful:
```
```
class ShowProperties {
    public static void main(String[] args) {
        System.getProperties().list(System.out);
    }
}
```
```
All it does is print out all the properties provided by your Java implementations. It'll give you an idea of what you can find out about your Java environment via properties. :-)