119.ArrayList

What is an ArrayList in Java?

• A type of linked list
• A resizable array
• A fixed-size array
• A mapping data structure

What are ArrayList and Vector in Java?

• Two types of maps
• Two types of sets
• Two types of lists
• Two types of queues

How can you create a 2D ArrayList in Java?

• ArrayList<ArrayList>
• 2DArrayList
• new ArrayList[2][2]
• ArrayList[2][2]

When should you use an ArrayList in Java?

• When memory is limited
• When a fixed size is needed
• When elements need to be sorted
• When elements need to be dynamically added or removed

What is the difference between ArrayList and arrays in Java?

• ArrayList is faster than arrays
• Arrays can store different data types
• Arrays are resizable, while ArrayList is not
• ArrayList provides dynamic resizing, while arrays have fixed sizes

How can you determine the size of an ArrayList in Java?

• Use length() method
• Use size() method
• Use getSize() method
• Use count() method

What is the purpose of the Vector class in Java?

• To create dynamic arrays
• To provide synchronization
• To store key-value pairs
• To perform mathematical operations

How does an ArrayList handle duplicates in Java?

• It removes duplicates automatically
• It throws an exception for duplicates
• It keeps all duplicates
• It sorts duplicates

What are the advantages of using an ArrayList?

• Constant time access
• Fixed size
• Automatic sorting
• Dynamic resizing

Can the size of an ArrayList increase dynamically in Java?

• No, it always has a fixed size
• Yes, it can increase or decrease dynamically
• Yes, but only by doubling the size
• No, the size must be specified at creation