code: public static Method getAccessibleMethod(Class<?> clazz, String methodName, Class<?>[] argTypes) {
          assertObjectNotNull("clazz", clazz);
          assertStringNotNullAndNotTrimmedEmpty("methodName", methodName);
          return findMethod(clazz, methodName, argTypes, VisibilityType.ACCESSIBLE, false);
      }
docs: Get the accessible method that means as follows:
  <pre>
  o target class's methods = all
  o superclass's methods   = public or protected
  </pre>
  @param clazz The type of class that defines the method. (NotNull)
  @param methodName The name of method. (NotNull)
  @param argTypes The type of argument. (NotNull)
  @return The instance of method. (NullAllowed: if null, not found)