code: public static <T> Constructor<T> findKnownConstructor(Class<T> aClass,
                                                            Class<?>... paramTypes)
      {
          try
          {
              return aClass.getConstructor(paramTypes);
          }
          catch (NoSuchMethodException ex)
          {
              // This cannot happen if the method is correctly identified.
              throw new IllegalArgumentException("Specified constructor does not exist in class " + aClass.getName(), ex);
          }
      }
docs: Looks up a constructor that is explicitly identified.  This method should only
  be used for constructors that definitely exist.  It does not throw the checked
  NoSuchMethodException.  If the constructor does not exist, it will instead fail
  with an unchecked IllegalArgumentException.
  @param <T> The type of object that the constructor creates.
  @param aClass The class in which the constructor exists.
  @param paramTypes The types of the constructor's parameters.
  @return The identified constructor.