import java.io.File;

public class main {

    public static void main(String[] args) {

        System.out.println("Verfügbarer Speicherplatz:\n");
        System.out.println(getDriveStorage() + " bytes");
        System.out.println(getDriveStorage()/1024 + " Kbytes");
        System.out.println(getDriveStorage()/1024/1024 + " Mbytes");
        System.out.println(getDriveStorage()/1024/1024/1024 + " Gbytes");
    }

    private static long getDriveStorage() {

        String laufwerk = "C:/";
        File f = new File(laufwerk);
        return f.getFreeSpace();

    }

}