Program Challenge

public class MethodInvoker {
  public static Object invokeMethod(
    Object instance,
    String name,
    Object... args)
}

import java.lang.reflect.Method;
import java.lang.reflect.InvocationTargetException;

public class MethodInvoker {
  public static Object invokeMethod(
    Object instance,
    String name,
    Object... args) {

      Object returnValue = null;

      try {
        Class theClass = instance.getClass();
        Class parameterTypes[] = new Class[args.length];
        for (int i=0, n=args.length; i<n; i++) {
          parameterTypes[i] = args[i].getClass();
        }
        Method method = theClass.getMethod(name, parameterTypes);
        returnValue = method.invoke(instance, args);
      } catch (NoSuchMethodException e) {
        System.err.println("Invalid method name: " + name);
      } catch (IllegalAccessException e) {
        System.err.println("Invalid method access: " + name);
      } catch (InvocationTargetException e) {
        System.err.println("Invalid method invocation:   + name);
      }
      return returnValue;
  }

  public static void main(String args[]) {
    // Test: "Hello, World".replaceAll("o", "a");
    System.out.println(
      MethodInvoker.invokeMethod(
              "Hello, World",
              "replaceAll",
              "o", "a"));
  }
}