A volatile keyword is used in a multithreading environment where two threads reading and writing the same variable simultaneously. The volatile keyword flushes the changes directly to the main memory instead of the CPU cache.
On the other hand, the transient keyword is used during serialization. Fields that are marked as transient can not be part of the serialization and deserialization. We don't want to save the value of any variable then we use transient keyword with that variable.
| Sr. No. | Key | Volatile | Transient |
|---|---|---|---|
| 1 | Basic | Volatile keyword is used to flush changes directly to the main memory | The transient keyword is used to exclude variable during serialization |
| 2. | Default value | Volatile are not initialized with a default value. | During deserialization, transient variables are initialized with a default value |
| 3 | Static | Volatile can be used with a static variable. | Transient can not be used with the static keyword |
| 4 | Final | Volatile can be used with the final keyword | Transient can not be used with the final keyword |
Example of Transient
// A sample class that uses transient keyword to
// skip their serialization.
class TransientExample implements Serializable {
transient int age;
// serialize other fields
private String name;
private String address;
// other code
}Example of Volatile
class VolatileExmaple extends Thread{
boolean volatile isRunning = true;
public void run() {
long count=0;
while (isRunning) {
count++;
}
System.out.println("Thread terminated." + count);
}
public static void main(String[] args) throws InterruptedException {
VolatileExmaple t = new VolatileExmaple();
t.start();
Thread.sleep(2000);
t.isRunning = false;
t.join();
System.out.println("isRunning set to " + t.isRunning);
}
}