Bug with Override annotations in Eclipse

This is most likely because you are switching between Java 1.5 and Java 1.6. In 1.5 you couldn't mark interface implementations with @Override, but you can in 1.6.

A quick Google search turned up this good explanation of the difference in this annotation between the two versions: http://www.techienuggets.com/CommentDetail?tx=38155

Semantics of @Override is different in JDK 1.5 and JDK 1.6. In JDK 1.5, the @Override annotation is not allowed for implementations of methods declared in an interface, while they are allowed in JDK 1.6. For more information, see:

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=5008260http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6399361http://blogs.oracle.com/ahe/?entry=override

It is fact that the description of the Override annotation was not updated in the JDK API docs. This has been reported as a bug:

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6501053bugdatabase/view_bug.do?bug_id=6501053

just go to

 window -> prefrences -> java -> compiler 

and set it to 1.6 as notation starts from 1.6 so if compilence level will less then 1.6 it will gives error

There are a few places where Java Compiler settings are configured.

One way is to Window->Preferences->Java->Compiler->Compiler Compliance Level -> set 1.6 or above.Another way is right click on the Project->Properties->Java Compiler->JDK Compliance -> Select 1.6 or above.

Also You can unselect "Enable Project Specific Settings" , this will eliminate future JDK compiler compliance errors. Remove Multiple instances of JDK Versions , unless different projects need them.