You can use a URLConnection object to send an HTTP request.
import java.io.PrintWriter;
import java.net.URL;
import java.net.URLConnection;
public class MainClass {
public static void main(String[] a)throws Exception {
URL url = new URL("http://www.yourdomain.com/form.jsp");
URLConnection connection = url.openConnection();
connection.setDoOutput(true);
PrintWriter out = new PrintWriter(connection.getOutputStream());
out.println("firstName=Joe");
out.println("lastName=Average");
out.close();
}
}