Java JNA touch

import com.sun.jna.*;
import com.sun.jna.ptr.*;

public class Touch {
    /** Definition of the C library. */
    interface CLibrary  extends Library {
        CLibrary INSTANCE = (CLibrary)Native.loadLibrary("c", CLibrary.class);

        public int utime(String filename, utimbuf buf);
    }

    public static class time_t extends Structure {
        public int value;

        public time_t() {}

        public time_t(int value) {
            this.value = value;
        }
    }

    public static class utimbuf extends Structure {
        public time_t actime;
        public time_t modtime;

        public utimbuf() {}

        public utimbuf(time_t actime, time_t modtime) {
            this.actime = actime;
            this.modtime = modtime;
        }
    }

        public static void main(String[] args) {
            CLibrary lib = CLibrary.INSTANCE;
            if (args.length < 2) {
                System.out.println("Usage: java Touch <filename> <unix time in seconds>");
                System.exit(1);
            }

            String filename = args[0];
            time_t filetime = new time_t(Integer.valueOf(args[1]));
            utimbuf buf = new utimbuf(filetime, filetime);
            System.out.println(CLibrary.INSTANCE.utime(filename, buf));
        }
    }