How do multiple threads read the latest updated information of a variable marked with the volatile keyword?

In Java, the keyword volatile guarantees that reading and writing a variable will occur directly from main memory, not from each thread's local cache. This means that when one thread modifies the value of a volatile variable, other threads will see the updated value on their next read.

Mechanism:

• When writing to a volatile variable, changes are immediately written to main memory.
• When reading a volatile variable, the thread reads the value from main memory, not from cache.

Thus, volatile provides visibility of changes between threads, preventing situations where one thread reads an outdated value.

Important: volatile does not guarantee atomicity of complex operations (e.g., increment), for which additional synchronization mechanisms are needed.