15.10.1. Unbounded Wildcards

Try these first

1. 1.

   What is the symbol for an unbounded wildcard in Java?

   Hint

   Think of a placeholder for any type.

2. 2.

   Which operation is not allowed with unbounded wildcards?

   Hint

   Remember, since the type is unknown, you cannot add.

3. 3.

   What does <?> represent in Java?

   • A specific type
   • Any type
   • A primitive type

   Hint

   Think of it as a placeholder.

4. 4.

   Can you add elements to a collection of type List<?>?

   • True
   • False

   Hint

   Consider what you can and cannot do with unknown types.

5. 5.

   Write a Java method that accepts a List<?> and counts the number of elements. Provide your reasoning.

   Hint

   Think about iterating through the list.

6. 6.

   Propose a scenario in application development where unbounded wildcards are particularly useful, explaining your reasoning.

   Hint

   Consider how libraries handle various data types.