Eclipse: always notice error when use @Override [duplicate]

Question

I don't know why each time I implements a class. when I use @Override Eclipse always notice error:

the method A of type B must override a superclass method

(With method A is method that I override and B is the current class I work with)

And Eclipse recommend delete @Override

But with the same code, I work on Idea, no error found.

Who can tell me why,please.

thanks :)

@Edit: Oh, I don't post exactly code because It happend for all when I implement sth: for example:

public class helloworld implements Runnable {
    @Override //this line no-error with Idea and error with eclipse:the method run of type helloworld must be override a super class
    public void run(){
    }

Answer 1

Java 5 only properly supports this annotation on methods you override when subclassing. Starting with Java 6 you can also use this annotation on methods that implement methods from an interface.