Complete Java SE 8 Developer Bootcamp - Maps

The video tutorial provides an in-depth look at maps in Java, focusing on their role in the collections framework. It explains the unique characteristics of maps, such as key-value pairs, and the importance of unique keys. The tutorial covers the HashMap implementation, detailing how to create and manipulate entries using methods like put, get, and remove. It also introduces TreeMap, highlighting its ability to maintain order. The video emphasizes the use of polymorphism and the significance of synchronizing equals and hashCode methods.

What is the primary reason maps are not part of the collection interface hierarchy?

• Maps use numeric indices.

• Maps have unique data structures and requirements.

• Maps are not part of the Java Util package.

• Maps are considered legacy.

Why can't maps have duplicate keys?

• It would make retrieval of specific objects ambiguous.

• It would slow down the map's performance.

• It would cause compilation errors.

• It would increase memory usage.

What is a common data type used for keys in a map?

• Float

• Boolean

• String

• Character

Which method is used to add key-value pairs to a hash map?

• insert

• put

• add

• append

What is the purpose of casting when retrieving objects from a hash map?

• To remove the object from the map.

• To increase the map's efficiency.

• To ensure the object is of the correct type.

• To convert the object to a string.

Which method checks if a specific key exists in a map?

• containsKey

• findKey

• searchKey

• hasKey

Why does the keySet method return a set?

• Because keys are always integers.

• Because keys must be unique.

• Because keys are always strings.

• Because keys can be duplicated.