15.9.2. Syntax

Try these first

1. 1.

   Define a list that holds integer values using Java generics.

   Hint

   Think about how to specify the type in the collection.

2. 2.

   What would happen if you try to add a string to a List?

   Hint

   Consider the type safety principle of generics.

3. 3.

   What does List<String> list = new ArrayList<>(); accomplish?

   • Creates a list for strings
   • Creates a list for integers
   • Creates a generic list that accepts any type

   Hint

   Consider what data types are allowed in the list.

4. 4.

   True or False: Generics allow for type safety in Java before runtime.

   • True
   • False

   Hint

   Think about when types are checked in the code.

5. 5.

   Create a generic method that swaps two elements in an array. What will be your method signature?

   Hint

   Consider how you'd swap values in a basic array before applying generics.

6. 6.

   How would you define a generic class that can store two elements of any type?

   Hint

   Think about how to accommodate two different types in the same class.