Re: Code review request for 6908218 "java.lang.Deprecated should have explicit @Target meta-annotation"

[Joseph D. Darcy]

Bruce Chapman wrote:
Joe,
there is information about the rationale for the change in this email 
but that information isn't in the bug report, Will it be put in the 
commit message or bug report?

Hi Bruce.

I'll at least add a link to the core-libs thread to the bug when I 
update the bug to fixed state.

-Joe


Bruce


Joseph D. Darcy wrote:
Hello.

Please review my patch to fix 6908218 "java.lang.Deprecated should 
have explicit @Target meta-annotation."

For background, JSR 308 added two new enum constants to ElementType.  
ElementType constants are used in java.lang.annotation.Target 
meta-annotations to indicate what kind of elements an annotation is 
applicable to.

If an annotation type does not have a @Target meta-annotation, 
annotations of the annotation type are allowed to be applied to all 
elements.  Therefore, after JSR 308 added new ElementTypes, 
annotations without @Target meta-annotations can now be applied to 
more kinds of things, perhaps inappropriately given the semantics of 
the annotation.

Conversely, annotations that do have a @Target meta-annotations might 
want to be applicable to the new locations.

Two adjustments should be done to platform annotations: @Deprecated 
should get an explicit @Target meta-annotation and @SuppressWarnings 
should be applicable to another ElementType:

--- old/src/share/classes/java/lang/Deprecated.java    2010-01-13 
22:30:49.000000000 -0800
+++ new/src/share/classes/java/lang/Deprecated.java    2010-01-13 
22:30:49.000000000 -0800
@@ -26,6 +26,7 @@
package java.lang;

import java.lang.annotation.*;
+import static java.lang.annotation.ElementType.*;

/**
 * A program element annotated @Deprecated is one that programmers
@@ -38,5 +39,6 @@
 */
@Documented
@Retention(RetentionPolicy.RUNTIME)
+...@target(value={CONSTRUCTOR, FIELD, LOCAL_VARIABLE, METHOD, PACKAGE, 
PARAMETER, TYPE})
public @interface Deprecated {
}
--- old/src/share/classes/java/lang/SuppressWarnings.java    
2010-01-13 22:30:50.000000000 -0800
+++ new/src/share/classes/java/lang/SuppressWarnings.java    
2010-01-13 22:30:49.000000000 -0800
@@ -26,7 +26,6 @@
package java.lang;

import java.lang.annotation.*;
-import java.lang.annotation.ElementType;
import static java.lang.annotation.ElementType.*;

/**
@@ -45,7 +44,7 @@
 * @since 1.5
 * @author Josh Bloch
 */
-...@target({TYPE, FIELD, METHOD, PARAMETER, CONSTRUCTOR, LOCAL_VARIABLE})
+...@target({TYPE, FIELD, METHOD, PARAMETER, CONSTRUCTOR, 
LOCAL_VARIABLE, TYPE_PARAMETER})
@Retention(RetentionPolicy.SOURCE)
public @interface SuppressWarnings {
    /**


For java.lang.Deprecated, the meta-annotation
@Target(value={CONSTRUCTOR, FIELD, LOCAL_VARIABLE, METHOD, PACKAGE, 
PARAMETER, TYPE})
includes all JDK 5/6 era locations annotations can be applied to.  
Therefore, with this list the locations @Deprecated can be applied 
will be unchanged from Java SE 6.

JLSv3 mandates warnings be issued for the use of a deprecated "type, 
method, field, or constructor" 
(http://java.sun.com/docs/books/jls/third_edition/html/interfaces.html#9.6.1.6).  
Other permitted applications of an @Deprecated annotation must be 
ignored; "Use of the annotation @Deprecated on a local variable 
declaration or on a parameter declaration has no effect."  Therefore, 
allowing @Deprecated on TYPE_PARAMETER or as a TYPE_USE would not be 
meaningful.

Webrev at:
http://cr.openjdk.java.net/~darcy/6908218.0/

Thanks,

-Joe