IS an Instance variable threadsafe?

[samir vasani]

Dear Expert,

Please explain me with the example.

[Kuma Phani]

Yes, instance variable in enum is threadsafe.

public enum BMW{

INSTANCE;

}

INSTANCE - is thread safe.

[Steve Luke]

Kuma Phani wrote:Yes, instance variable in enum is threadsafe.

Can you answer why that particular type of reference is thread safe?

If the question is if, in general, variables belonging to an instance are thread safe, the answer is no. If the question is if a variable belonging to an instance can be made thread safe, the answer is yes. Here is an example of an instance variable that is not safe:

public class AClass
{
    public int aVariable = 10;
}

Here is an example of one that is safe:

public final class BClass
{
    public final int bVariable = 10;
}

[Tim Holloway]

Kuma Phani wrote:Yes, instance variable in enum is threadsafe.

public enum BMW{

INSTANCE;

}

INSTANCE - is thread safe.

FALSE

No variable or object in Java is intrinsically threadsafe. If an object is accessible by 2 different threads, they can totally slaughter it.

To be threadsafe, mechanisms must be employed to enforce threadsafe access. The most common mechanism used for this purpose is Java's built-in "synchronized" capabilities. You use the "synchronized" modifier to ensure that critical properties, methods, or even the class instance as a while are only accessed according to proper threading protocols.

Nothing is synchronized by default, however.

For an example of a class whose methods have been made threadsafe, look at the java StringBuffer class. Then contrast it with the newer and non-threadsafe StringBuilder class.