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  1. JDK
  2. JDK-8138569

5.4.3.5: Clarify that method handle resolution is static-aware

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P4
    • Resolution: Fixed
    • Affects Version/s: 8
    • Fix Version/s: 9
    • Component/s: specification
    • Labels:
    • Subcomponent:
      vm

      Description

      Method handle resolution is not specified to perform checks of ACC_STATIC flag of the target field or method. Yet, HotSpot performs checks as follows:
      - If method handle kind is one of REF_getField, REF_putField, REF_invokeVirtual, REF_invokeSpecial or REF_invokeInterface and the referenced field or method IS static then IllegalAccessError is thrown.
      - If method handle kind is one of REF_getStatic, REF_putStatic or REF_invokeStatic and the referenced field or method IS NOT static then IllegalAccessError is thrown.

      These rules are akin to ACC_STATIC checks in the corresponding instructions throwing IncompatibleClassChangeError.

      Note that there is no need for the check for REF_newInvokeSpecial because it cannot refer to a static method <init>:()V due to the following restrictions:
      - JVMS 4.4.8 only permits method of a class (not an interface) named <init> to be referenced by REF_newInvokeSpecial.
      - JVMS 4.4.2 only permits CONSTANT_Methodref_info to refer method <init> if it has a return type void.
      - JVMS 2.9 (of version presented in JDK-8122940) defines all methods <init>:()V declared in a class (not interface) to be instance initialization methods.
      - JVMS 4.6 prohibits setting ACC_STATIC for instance initialization methods.

      Example:
      public class StaticTest version 52:0 {
          public static Method main:"([Ljava/lang/String;)V" stack 10 locals 1 {
              // Each ldc instruction throws IllegalAccessError
              ldc MethodHandle REF_getField:staticF:I;
              ldc MethodHandle REF_putField:staticF:I;

              ldc MethodHandle REF_getStatic:f:I;
              ldc MethodHandle REF_putStatic:f:I;

              ldc MethodHandle REF_invokeVirtual:staticM:"()V";
              ldc MethodHandle REF_invokeSpecial:staticM:"()V";

              ldc MethodHandle REF_invokeStatic:m:"()V";

              ldc MethodHandle REF_invokeInterface:Intf.staticIntfM:"()V";

              return;
          }

          public Field f:I;
          public static Field staticF:I;

          public Method m:"()V" stack 0 locals 1 { return; }
          public static Method staticM:"()V" stack 0 locals 1 { return; }
      }
      interface Intf version 52:0 {
          public static Method staticIntfM:"()V" stack 0 locals 1 { return; }
      }

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              • Assignee:
                abuckley Alex Buckley
                Reporter:
                slukyanov Stanislav Lukyanov (Inactive)
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                • Created:
                  Updated:
                  Resolved: