Execute an OS Command

public static void main (String [] args) throws IOException {

String [] Command = null;

if (System.getProperty("os.name").equals("Linux")) {
Command = new String[1];
Command[0] = "df";
}
if (System.getProperty("os.name").equals("Solaris")) {
Command = new String[2];
Command[0] = "df";
Command[1] = "-k";
}
if (Command == null) {
System.out.println("Can't find free space on this OS");
System.exit(1);
}

Process Findspace = Runtime.getRuntime().exec(Command);

BufferedReader Resultset = new BufferedReader(
new InputStreamReader (
Findspace.getInputStream()));

String line;
while ((line = Resultset.readLine()) != null) {
System.out.println(line);
}
}
}