@override annotation not working correctly javac version _ 1.7.0_25

Hi!

This code should output:

Run method overridden in Task class
overridden method run() in PeriodicTask class

but I'm having this :

# javac -version
javac 1.7.0_25

# javac CollectionTest.java
CollectionTest.java:18: error: incompatible types
    @Override
     ^
  required: Annotation
  found: Override
CollectionTest.java:27: error: incompatible types
    @Override
     ^
  required: Annotation
  found: Override
2 errors

/**
 * Java program to demonstrate how to override method in Java.
 * Overridden method are resolved during runtime based upon type of object
 * @author Javin
 */
public class CollectionTest {
  
    public static void main(String args[]) {
      Runnable task = new Task();
      task.run(); //call overridden method in Task
      task = new PeriodicTask();
      task.run(); //calls overridden method in PeriodicTas
    }
  
  
}

class Task implements Runnable{
    @Override
    public void run() {
        System.out.println("Run method overridden in Task class");
    }
}

class PeriodicTask extends Task{
    @Override
    public void run() {
        System.err.println("overridden method run() in PeriodicTask class");
    }
}