Java. Can you explain me the following code?

public class NFE {

public static void main(String[] args) {

String s = "42";

try {

s = s.concat(".5");

double d = Double.parseDouble(s);

s = Double.toString(d);

int x = (int)

Math.ceil(Double.valueOf(s).doubleValue());

System.out.println(x);

} catch (NumberFormatException e) {

System.out.println("bad number");

}

}

}