22.11. Stream API and Lambda Expressions

Try these first

1. 1.

   What is the purpose of the Stream API in Java?

   Hint

   Think about how it allows operations to be performed on collections.

2. 2.

   What is a lambda expression?

   Hint

   Recall the syntax: (parameters) -> expression.

3. 3.

   What operation would you use to remove elements that do not meet a condition in a Stream?

   • Map
   • Filter
   • Reduce

   Hint

   Consider which operation narrows down the elements.

4. 4.

   True or False: Lambda expressions can express behaviors that are passed into methods.

   • True
   • False

   Hint

   Think about the flexibility they provide in method parameters.

5. 5.

   Write a method that returns a List of squared values from an input List of integers using the Stream API.

   Hint

   Think about what map will do with the elements.

6. 6.

   Using the Stream API, how would you count the total number of words in a list of sentences?

   Hint

   Consider how to break down the sentences into their components.