code: public Method findMethod(final Class<?> clazz) {
  		Assert.notNull(clazz, "class must not be null");
  		final AtomicReference<Method> annotatedMethod = new AtomicReference<Method>();
  		ReflectionUtils.doWithMethods(clazz, new ReflectionUtils.MethodCallback() {
  			public void doWith(Method method)
  					throws IllegalArgumentException, IllegalAccessException {
  				Annotation annotation = AnnotationUtils.findAnnotation(method,
  						annotationType);
  				if (annotation != null) {
  					Assert.isNull(annotatedMethod.get(),
  							"found more than one method on target class [" + clazz
  									+ "] with the annotation type [" + annotationType
  									+ "]");
  					annotatedMethod.set(method);
  				}
  			}
  		});
  		return annotatedMethod.get();
  	}
docs: Find a <em>single</em> Method on the given Class that contains the annotation type
  for which this resolver is searching.
  @param clazz the Class instance to check for the annotation
  @return a single matching Method instance or <code>null</code> if the Class
  contains no Methods with the specified annotation
  @throws IllegalArgumentException if more than one Method has the specified
  annotation