RFR: 8309819: Clarify API note in Class::getName and MethodType::toMethodDescriptorString [v5]

[Mandy Chung]

On Thu, 15 Jun 2023 02:38:08 GMT, Chen Liang <liach at openjdk.org> wrote:

>> The API specification for descriptorString not being a strict inverse of Class::forName and MethodType::fromDescriptorString are not entirely correct.
>> 
>> 1. Class::descriptorString was never an inverse of Class::forName, which takes a binary name instead. Class::getName was a partial inverse instead.
>> 2. MethodType::toMethodDescriptorString ends with a meaningless sentence: "fromMethodDescriptorString, because the latter requires a suitable class loader argument.", and the "Note:" section can be replaced with an `@apiNote`.
>> 3. Both of these didn't mention hidden classes (or other non-nominally-describable classes) as a reason that prevents the inversion operation, in addition to distinct classloaders.
>> 
>> A few user-defined anchor links are replaced with updated javadoc link tag format as well. The explicit html-style links in `@see` tags are unchanged in order to retain the non-code output.
>> 
>> The rendered specifications:
>> https://cr.openjdk.org/~liach/8309819/04/java.base/java/lang/Class.html
>> https://cr.openjdk.org/~liach/8309819/04/java.base/java/lang/invoke/MethodType.html
>
> Chen Liang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update the note for getName

For `Class::getName`, I think #14528 should clarify it.

For `MethodType`, I suggest the following:

--- a/src/java.base/share/classes/java/lang/invoke/MethodType.java
+++ b/src/java.base/share/classes/java/lang/invoke/MethodType.java
@@ -1161,28 +1161,29 @@ class MethodType
     }
 
     /**
-     * Finds or creates an instance of a method type, given the spelling of its bytecode descriptor.
-     * Convenience method for {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
+     * Finds or creates an instance of a method type of the given method descriptor
+     * (JVMS {@jvms 4.3.3}). This method is a convenience method for
+     * {@link #methodType(java.lang.Class, java.lang.Class[]) methodType}.
      * Any class or interface name embedded in the descriptor string will be
-     * resolved by the given loader (or if it is null, on the system class loader).
+     * resolved by the given loader (or if it is {@code null}, on the system class loader).
      *
      * @apiNote
      * It is possible to encounter method types which cannot be
      * constructed by this method, because their component types are
-     * not all reachable from a common class loader, or some component types
-     * cannot be {@linkplain ##descriptor described nominally}.
+     * not visible from a common class loader.
      * <p>
      * This method is included for the benefit of applications that must
      * generate bytecodes that process method handles and {@code invokedynamic}.
      * @param descriptor a bytecode-level type descriptor string "(T...)T"
      * @param loader the class loader in which to look up the types
      * @return a method type matching the bytecode-level type descriptor
-     * @throws NullPointerException if the string is null
-     * @throws IllegalArgumentException if the string is not well-formed
+     * @throws NullPointerException if the string is {@code null}
+     * @throws IllegalArgumentException if the string is not a method descriptor
      * @throws TypeNotPresentException if a named type cannot be found
      * @throws SecurityException if the security manager is present and
      *         {@code loader} is {@code null} and the caller does not have the
      *         {@link RuntimePermission}{@code ("getClassLoader")}
+     * @jvms 4.3.3 Method Descriptors
      */
     public static MethodType fromMethodDescriptorString(String descriptor, ClassLoader loader)
         throws IllegalArgumentException, TypeNotPresentException
@@ -1230,7 +1231,7 @@ class MethodType
      * fromMethodDescriptorString} which requires a method type descriptor
      * (JVMS {@jvms 4.3.3}) and a suitable class loader argument. Two distinct
      * classes which share a common name but have different class loaders will
-     * appear identical when viewed within descriptor strings.
+     * have the identical descriptor strings.
      * <p>
      * This method is included for the benefit of applications that must
      * generate bytecodes that process method handles and {@code invokedynamic}.


With these clarification, would you think it's clearer?  CNFE or IAE is thrown for the negative cases and no need to mention in API note.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/14411#issuecomment-1595250196