Thursday, March 12, 2009

@Override annotation

After back from New Zealand, this the first time i officially used Java 5 and above to do coding, it is bit hard for me to code in Java 5, because i am not familiar with the Java 5 new features such as annotation, generics , boxing unboxing those stuffs.

And this @Override annotation had made me struggle for few hours. According to Javadoc,

Indicates that a method declaration is intended to override a method declaration in a superclass. If a method is annotated with this annotation type but does not override a superclass method, compilers are required to generate an error message.

So i assume this code will work fine:
interface K {
void method1();

class A implements K {
public void method1() {

But the compiler complains about it and giving the error: “The method method1() of type A must override a superclass method”.

I don't know what is strong with the code, i thought maybe i used it in the wrong way at the beginning, i tested up with different case, end up i found out @Override annotation seems only applied to methods overridden from a superclass and not from Interfaces, i guess this is because implements interface but not override ! This had wasted my few hours !

However, this case not applied to Java 6, i switch compiler version to Java 6 and everything work fine. Weird !

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