Java tutorial
import static java.lang.System.out; import java.lang.reflect.InvocationTargetException; public class Main { public Main() { } public Main(Integer i) { } public Main(Object o) { out.format("Constructor passed Object%n"); } public Main(String s) { out.format("Constructor passed String%n"); } public static void main(String... args) { String argType = (args.length == 0 ? "" : args[0]); try { Class<?> c = Class.forName("Main"); if ("".equals(argType)) { // IllegalArgumentException: wrong number of arguments Object o = c.getConstructor().newInstance("foo"); } else if ("int".equals(argType)) { // NoSuchMethodException - looking for int, have Integer Object o = c.getConstructor(int.class); } else if ("Object".equals(argType)) { // newInstance() does not perform method resolution Object o = c.getConstructor(Object.class).newInstance("foo"); } else { assert false; } // production code should handle these exceptions more gracefully } catch (ClassNotFoundException x) { x.printStackTrace(); } catch (NoSuchMethodException x) { x.printStackTrace(); } catch (InvocationTargetException x) { x.printStackTrace(); } catch (InstantiationException x) { x.printStackTrace(); } catch (IllegalAccessException x) { x.printStackTrace(); } } }