How does Map behave in multithreaded code?

In Java, the behavior of Map in multithreaded code can exhibit issues such as data inconsistency and unexpected results if proper synchronization is not implemented. Most standard implementations of Map, such as HashMap, are not thread-safe, meaning that concurrent access by multiple threads can lead to unpredictable behavior.

To safely use Map in multithreaded environments, it is advisable to either use a synchronized wrapper around the Map or utilize concurrent collections like ConcurrentHashMap that are designed for concurrent access.