Error on @Override annotation with interface implementation

Question

I am using JRE 1.6 version and aware of JRE 1.5 trouble while using @Override with interface.

I imported a new project (Spring + Maven ) and Eclipse giving error on every @Override annotation whenever any interface method is overridden.

Things I tried till now

1. Checked project and workspace specific JRE and compliance level, It is set to 1.6 version.
   
2. Checked JRE library on build path, it is also same.
3. Changed Java version in project facet to 1.6 (Dont know if it will help)
   
4. Did Maven clean and install (hundred times till now)
5. Disabled error / warning for Annotations still no luck
6. Eclipse restart (Stupid thing but helps me lots of time)
7. Last option will be deleting all .setting and .project files if I dont get anything else to try.

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Edit 1:
I am getting following error

The method XXX of type XXX must override a superclass method.        

---

Edit 2:
Code Sample
Interface declaration

public interface HelperService {   
    public RequisitionTypeDTO getRequisitionTypeDTO(int id) throws Exception;  
}    

Implementation:

   @Service
   public class HelperServiceImpl implements HelperService{   
   @Override  // Getting error for this line
   public RequisitionTypeDTO getRequisitionTypeDTO(int id) throws Exception{
                         // Bla Bla Bla 
      }  
   }     

---

EDIT 3:
I am able to build and run my application successfully irrespective of this errors. Just not happy with red error flags all over the source code.

Answer 1

Check if the RequisitionTypeDTO in interface is the same type as RequisitionTypeDTO in implementation (different imports).

If ok then try adding maven-compiler-plugin

<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.5.1</version>
            <configuration>
                <source>1.6</source>
                <target>1.6</target>
            </configuration>
        </plugin>
    </plugins>
</build>

and Maven->Update project configuration... from context menu of your project - because that is the way you should set compilation jre.

And of course try mvn clean, in Eclipse Project->Clean...

If everything fails create new simple project with minimal code and check if there is the same error.

Answer 2

I got this too, and I did have a "Java Builder" set. Further investigation showed that the problem was that my "Compiler Compliance Level" was set to 1.5 rather than 1.6.