TreeMap Operations and Concepts in Java

In this Java tutorial, Brian introduces the map interface, focusing on the TreeMap class. He explains how the map interface maps keys to values, using employee IDs as an example. The tutorial covers creating a TreeMap with generics, adding entries using the put method, and retrieving entries with the get method. Brian demonstrates how to iterate over a TreeMap and highlights the importance of key ordering. The video concludes with a practical example of handling duplicate keys and the impact on value storage.

What does the Map interface in Java do?

• Maps objects to classes

• Maps keys to values

• Maps classes to objects

• Maps values to keys

In the context of TreeMap, what are generics used for?

• To specify the type of interfaces

• To specify the type of classes

• To specify the type of methods

• To specify the type of keys and values

What is the correct way to initialize a TreeMap with Integer keys and String values?

• TreeMap employees = new TreeMap<>();

• TreeMap employees = new TreeMap<>();

• TreeMap employees = new TreeMap<>();

• TreeMap employees = new TreeMap<>();

Which method is used to add elements to a TreeMap?

• append()

• insert()

• put()

• add()

What happens if you add an element with a key that already exists in the TreeMap?

• The new element is ignored

• Both elements are stored

• The old element is overwritten

• An error is thrown

How can you retrieve an element from a TreeMap using its key?

• employees.get(key)

• employees.retrieve(key)

• employees.find(key)

• employees.search(key)

Which method can be used to check if a key exists in a TreeMap?

• keyExists()

• hasKey()

• findKey()

• containsKey()

What does the keySet() method in a TreeMap return?

• A set of all values

• A set of all keys

• A list of all entries

• A list of all values

In what order does a TreeMap store its keys?

• Insertion order

• Random order

• Natural order

• Reverse order

What happens to the order of elements when a key with a lower value is added to a TreeMap?

• The elements are reordered by key

• The new key is added at the beginning

• The new key is added at the end

• The order remains the same