Here's an example of using @SuppressWarnings to suppress a deprecation warning:

class Test {

    @Deprecated
    interface Foo { }

    @SuppressWarnings("deprecation")
    interface Bar extends Foo { }
}

Now consider the case where Foo and Bar are in separate source files:

Foo.java:

  @Deprecated
  interface Foo { }

Bar.java

  @SuppressWarnings("deprecation")
  interface Bar extends Foo { }

In that case it doesn't seem to be possible to suppress the warning:

$ javac -Xlint:all Foo.java Bar.java
Bar.java:2: warning: [deprecation] Foo in unnamed package has been deprecated
interface Bar extends Foo { }
                      ^
1 warning