JAVA : VOLATILE variable

JAVA : VOLATILE variable

Volatile - easily evaporated from cpu cache

By declaring the counter variable volatile all writes to the counter variable will be written back to main memory immediately.

The volatile keyword in Java is used as an indicator to Java compiler and Thread that do not cache value of this variable and always read it from main memory

Instead of synchronized variable in Java, you can have java volatile variable, which will instruct JVM threads to read value of volatile variable from main memory and don't cache it locally. If a variable is not shared between multiple threads no need to use volatile keyword with that variable

public class SharedObject {

    public int counter = 0;

}

public class SharedObject {

    public volatile int counter = 0;

}