15.5.3. Common Methods

Try these first

1. 1.

   What does the put method do in a Map?

   Hint

   Think about what adding means in the context of storing values.

2. 2.

   What will get('B') return if key 'B' does not exist in the Map?

   Hint

   Consider the behavior of retrieving a value that isn't there.

3. 3.

   What does the put method do in a Map?

   • Retrieves a value
   • Adds or updates a key-value pair
   • Removes an entry

   Hint

   Think about adding new data vs. retrieving it.

4. 4.

   True or False: The remove method returns null if the specified key does not exist in the Map.

   • True
   • False

   Hint

   Consider the way removal works without altering the structure adversely.

5. 5.

   Write a Java program that simulates a simple phonebook using a Map. The program should allow adding, retrieving, and removing contact entries by phone number (key) and name (value).

   Hint

   Think about how you would structure your Map and what methods you would include.

6. 6.

   Challenge to optimize a real-world application (like a bookstore) using Maps. Outline how you would handle inventory management with key-value pairs.

   Hint

   Reflect on how Maps can simplify data associations in complex applications.