Question

I am trying to use the @Deprecated annotation. The @Deprecated documentation says that: “Compilers warn when a deprecated program element is used or overridden in non-deprecated code”. I would think this should trigger it, but it did not. javac version 1.7.0_09 and compiled using and not using -Xlint and
-deprecation.

public class TestAnnotations {

   public static void main(String[] args)
   {
      TestAnnotations theApp = new TestAnnotations();
      theApp.thisIsDeprecated();
   }

   @Deprecated
   public void thisIsDeprecated()
   {
      System.out.println("doing it the old way");
   }
}

Edit: per the comment of gd1 below regarding it only working if the method is in another class, I added a second class. And it DOES WARN on the call to theOldWay():

public class TestAnnotations {

   public static void main(String[] args)
   {
      TestAnnotations theApp = new TestAnnotations();
      theApp.thisIsDeprecated();
      OtherClass thatClass = new OtherClass();
      thatClass.theOldWay();
   }

   @Deprecated
   public void thisIsDeprecated()
   {
      System.out.println("doing it the old way");
   }
}

class OtherClass {

   @Deprecated
   void theOldWay()
   {
      System.out.println("gone out of style");
   }


}

The warning:

/home/java/TestAnnotations.java:10: warning: [deprecation]
theOldWay() in OtherClass has been deprecated

    thatClass.theOldWay();
             ^

1 warning

Answer 1

From the Java Language Specification:

A Java compiler must produce a deprecation warning when a type,
method, field, or constructor whose declaration is annotated with the
annotation @Deprecated is used (i.e. overridden, invoked, or
referenced by name), unless:

• The use is within an entity that is itself annotated with the annotation @Deprecated; or

• The use is within an entity that is annotated to suppress the warning with the annotation @SuppressWarnings(“deprecation”); or

• The use and declaration are both within the same outermost class.

Your example is an example of the last condition: you’re only using the deprecated method from the same outermost class as the deprecated method.