JEP 211: Elide Deprecation Warnings on Import Statements
|Author||Joseph D. Darcy|
|Status||Closed / Delivered|
|Component||tools / javac|
|Discussion||compiler dash dev at openjdk dot java dot net|
|Reviewed by||Brian Goetz|
|Endorsed by||Brian Goetz|
As of Java SE 8, java compilers are required by reasonable interpretations of the Java Language Specification to issue deprecation warnings when a deprecated type is imported by name or when a deprecated member (method, field, nested type) is imported statically. These warnings are uninformative and should not be required. Deprecation warnings at actual uses of deprecated members should remain.
The goal of this JEP is to facilitate making large code bases clean of
lint warnings. The deprecation warnings on imports cannot be
suppressed using the
@SuppressWarnings annotation, unlike uses of
deprecated members in code. In large code bases like that of the JDK,
deprecated functionality must often be supported for some time and
merely importing a deprecated construct does not justify a warning
message if all the uses of the deprecated construct are intentional
It is not a goal of this JEP to actually resolve all the deprecation warnings in the JDK code case. However, that might occur as part of a separate maintenance effort in JDK 9.
From a specification perspective, the needed change is small. In JLS 8 the
A Java compiler must produce a deprecation warning when a type, method, field, or constructor whose declaration is annotated with
@Deprecatedis used (overridden, invoked, or referenced by name) in a construct which is explicitly or implicitly declared, unless:
- The use is within an entity that is itself annotated with the annotation
- The use is within an entity that is annotated to suppress the warning with the annotation
- The use and declaration are both within the same outermost class.
The specification change would be something like adding another bullet stating the additional exclusion:
- The use is within an
javac reference implementation, there would be a simple check
to skip over import statements when looking for deprecation warnings.
Normal unit tests should suffice to test this feature. A handful of JCK tests may need to be updated for the changed specification.