Core Java Programming Course- Hash Map

The video tutorial explains the concept of HashMap in Java, detailing its implementation as a key-value pair data structure similar to a dictionary. It covers creating a HashMap, adding, retrieving, updating, and removing entries, and using operations like 'contains key'. The tutorial also demonstrates converting a HashMap into sets of keys, values, and entries, and concludes with a summary of the discussed operations.

What is a HashMap in Java similar to in other programming languages?

• Array

• Dictionary

• Queue

• Stack

Which method is used to add entries to a HashMap?

• add

• append

• insert

• put

How can you retrieve a value from a HashMap?

• Using the value

• Using the index

• Using the key

• Using the size

What does the containsKey method do?

• Adds a new key-value pair

• Checks if a key is present

• Checks if a value is present

• Removes a key-value pair

How do you update an existing value in a HashMap?

• Use the modify method

• Use the put method with the existing key

• Use the update method

• Use the change method

What happens when you use the clear method on a HashMap?

• It removes only the keys

• It removes only the values

• It removes all entries

• It removes a single entry

How can you convert a HashMap into a set of its keys?

• Using the convert method

• Using the entrySet method

• Using the values method

• Using the keySet method