Detectar que SO se esta usando desde java

OSValidator.java

public class OSValidator {
 
	public static void main(String[] args) {
		if (isWindows()) {
			System.out.println("This is Windows");
		} else if (isMac()) {
			System.out.println("This is Mac");
		} else if (isUnix()) {
			System.out.println("This is Unix or Linux");
		} else if (isSolaris()) {
			System.out.println("This is Solaris");
		} else {
			System.out.println("Your OS is not support!!");
		}
	}
 
	public static boolean isWindows() {
 
		String os = System.getProperty("os.name").toLowerCase();
		// windows
		return (os.indexOf("win") >= 0);
 
	}
 
	public static boolean isMac() {
 
		String os = System.getProperty("os.name").toLowerCase();
		// Mac
		return (os.indexOf("mac") >= 0);
 
	}
 
	public static boolean isUnix() {
 
		String os = System.getProperty("os.name").toLowerCase();
		// linux or unix
		return (os.indexOf("nix") >= 0 || os.indexOf("nux") >= 0);
 
	}
 
	public static boolean isSolaris() {
 
		String os = System.getProperty("os.name").toLowerCase();
		// Solaris
		return (os.indexOf("sunos") >= 0);
 
	}
 
}