What is the internal working of HashMap and HashSet? What is the difference between ArrayList and LinkedList? Why is StringBuilder non-synchronized? If there is a bank account service being called multiple times for deposit and withdrawal, how would you manage the account balance and process transactions accordingly?(Using Synchronized)

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Accepted Answer

HashMap and HashSet use hashing for fast retrieval, ArrayList uses dynamic array, LinkedList uses linked nodes. StringBuilder is non-synchronized for performance. Synchronized blocks can be used to manage bank account balance.

HashMap uses key-value pairs and hashing for fast retrieval, while HashSet uses hashing for unique elements.
ArrayList uses dynamic array for fast random access, while LinkedList uses linked nodes for fast insertion and deletion.
StringBuilder is non-synchronized for better performance in single-threaded environments.
Synchronized blocks can be used in bank account service to ensure thread safety and manage account balance during multiple transactions.

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