What is the Purpose of the `volatile` Keyword in Java?

What is the purpose of the `volatile` keyword in Java?

// Example of using volatile keyword
public class SharedResource {
    private volatile int counter = 0;

    public void increment() {
        counter++;
    }

    public int getCounter() {
        return counter;
    }
}

The `volatile` keyword in Java is crucial for managing shared data between threads. It indicates that a variable's value will be modified by different threads, ensuring visibility and preventing caching issues.

// Declaring a volatile variable in Java
volatile boolean isRunning = true; // used in a running state check

Causes

• Ensures visibility of changes made by one thread to other threads
• Prevents thread-local caching of volatile variables

Solutions

• Use `volatile` for variables that are accessed by multiple threads to ensure visibility of updates
• In cases where the value is being updated multiple times, consider `Atomic` classes or `synchronized` methods for safer operations

Mistake: Misunderstanding the scope of volatile variables; assuming it guarantees atomicity.

Solution: Remember that `volatile` only guarantees visibility; use synchronization for atomic operations.

Mistake: Using `volatile` on complex data types which may have mutable states.

Solution: Prefer `Atomic` classes for dealing with complex shared data or implement proper synchronization.