Final answer:
The 'thing' class is missing a constructor and a String attribute.
Step-by-step explanation:
The 'thing' class is missing a constructor and a String attribute. Constructors are special methods used to initialize the objects of a class, and a String attribute is a variable that holds a sequence of characters.
By adding a constructor, you can specify how to create instances of the 'thing' class, and by adding a String attribute, you can store and access a string value within the class.