Selenium WebDriver with Java - Basics to Advanced and Frameworks - Implementing Map Interface

This lecture covers the concept of HashMap in Java, focusing on its implementation and usage. It explains how HashMap stores data in key-value pairs, demonstrates adding and retrieving elements, and discusses handling null values. The lecture also explores converting HashMap to a set and iterating over it using an iterator. Additionally, it explains how to separate keys and values using Map.Entry, providing a deeper understanding of HashMap operations.

What is the primary function of the 'put' method in a HashMap?

• To remove a key-value pair

• To sort the HashMap

• To update the HashMap size

• To add a new key-value pair

How does a HashMap store its data?

• As a single array

• As a key-value pair

• In a list format

• In a tree structure

What happens when you try to retrieve a value with a non-existent key in a HashMap?

• It returns null

• It creates a new key

• It returns a default value

• It throws an error

What is the result of removing a key from a HashMap?

• The HashMap is cleared

• The key is set to null

• The key-value pair is deleted

• The value is set to zero

What is an entry set in the context of a HashMap?

• A set of indices

• A set of key-value pairs

• A set of values

• A set of keys

How can you iterate over a HashMap's entry set?

• Using a map function

• Using a while loop

• Using an iterator

• Using a for loop

What is the purpose of using Map.Entry in a HashMap?

• To combine keys and values

• To separate keys and values

• To sort the HashMap

• To remove duplicates

What error might occur if you try to print a HashMap entry without using Map.Entry?

• IllegalArgumentException

• ClassCastException

• NullPointerException

• IndexOutOfBoundsException

Why is it necessary to cast a HashMap entry to Map.Entry?

• To increase security

• To reduce memory usage

• To enable key-value separation

• To improve performance

What is the outcome of iterating over a HashMap without casting to Map.Entry?

• It duplicates entries

• It throws an error

• It returns null

• It works fine