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  1. JDK
  2. JDK-8245664

javac erroneously issues deprecation warning for use of a deprecated package

    Details

    • Type: Bug
    • Status: Open
    • Priority: P4
    • Resolution: Unresolved
    • Affects Version/s: None
    • Fix Version/s: 16
    • Component/s: tools
    • Labels:
      None

      Description

      The java.lang.Deprecated annotation type specification says,

      «Use of the @Deprecated annotation on a local variable declaration or on a parameter declaration or a package declaration has no effect on the warnings issued by a compiler.»

      Note however that @Deprecated is allowed on package declarations for reasons of backward compatibility.

      https://docs.oracle.com/en/java/javase/14/docs/api/java.base/java/lang/Deprecated.html

      JLS 9.6.4.6 specifies requirements that warnings be generated when certain deprecated program elements are mentioned, and packages are omitted from the list of program elements.

      https://docs.oracle.com/javase/specs/jls/se14/html/jls-9.html#jls-9.6.4.6

      With these points in mind, consider the following source files:

      p/package-info.java
      ===================

      @Deprecated
      package p;


      p/P.java
      ========

      package p;
      public class P { }

      q/Q.java
      ========
      package q;
      import p.*;
      class Q {
          Class<?> c1 = P.class; // **1**
          Class<?> c2 = p.P.class; // **2**
      }


      Compiling all of files with "javac -Xlint:deprecation */*.java" results in:

      ==========
      p/package-info.java:2: warning: [deprecation] @Deprecated annotation has no effect on this package declaration
      package p;
              ^
      q/Q.java:5: warning: [deprecation] p in has been deprecated
          Class<?> c2 = p.P.class;
                        ^
      2 warnings
      ==========

      The first warning is probably ok, as it warns that the deprecation has no effect. (See JDK-8140772.)

      The second warning is very strange, as it *IS* an effect of deprecating package p. Note that using a member of package p via on-demand import, as in line **1**, does not issue a warning. However, line **2**, which mentions package p as part of a full qualification of a class name, does issue a warning. Note also the malformed warning message.

      This is rather strange, and it ought to be straightened out.

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              • Assignee:
                jlahoda Jan Lahoda
                Reporter:
                smarks Stuart Marks
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                Dates

                • Created:
                  Updated: