Implementing Marker Interfaces in Java

Question

I want to implement a marker interface that suggests user to define a value like serialVersionUID that is suggested when a Class implements java.io.Serializable . How can I achieve it in Java?

Thanks in advance!!

Answer 1

If you can go the annotation way you can implement a custom annotation with a (required) element. Elements that do not have a default value are required .

For instance look at the following annotation:

public @interface Deprecated {
    String version(); //In which version this was deprecated?
    String reason() default "[not documented]";
}

Here version is a required field, while you can omit the reason field when annotating something.

For more information, you can look at this tutorial: http://howtodoinjava.com/2014/06/09/complete-java-annotations-tutorial/