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  1. JDK
  2. JDK-8024647

Default method resolution with private superclass method

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P3
    • Resolution: Fixed
    • Affects Version/s: None
    • Fix Version/s: hs25
    • Component/s: hotspot
    • Subcomponent:
    • Resolved In Build:
      b51

      Backports

        Description

        The currently-specified behavior of resolution is that a private class method takes priority over an interface method. (This is a problem -- see JDK-8021581.)

        When default methods are involved, this rule is not being followed, and there are some inconsistencies.

        Example 1 is the expected behavior for all 3 cases.

        There may be some similar inconsistencies when package-access methods are involved.

        -----
        Example 1 (no default):

        public class A {
         private void m() { System.out.println("A.m"); }
         public static void main(String... args) { B b = new C(); b.m(); }
        }

        public interface I {
         public void m();
        }

        public abstract class B extends A implements I {
        }

        public class C extends B {
         public void m() { System.out.println("C.m"); }
        }

        public class Test {
         public static void main(String... args) { B b = new C(); b.m(); }
        }

        java Test
        Exception in thread "main" java.lang.IllegalAccessError: tried to access method A.m()V from class Test

        java A
        A.m

        -----
        Example 2 (default, overridden):

        public class A {
         private void m() { System.out.println("A.m"); }
         public static void main(String... args) { B b = new C(); b.m(); }
        }

        public interface I {
         public default void m() { System.out.println("I.m"); }
        }

        public abstract class B extends A implements I {
        }

        public class C extends B {
          public void m() { System.out.println("C.m"); }
        }

        public class Test {
         public static void main(String... args) { B b = new C(); b.m(); }
        }

        java Test
        C.m

        java A
        C.m

        -----
        Example 3 (default, not overridden):

        public class A {
         private void m() { System.out.println("A.m"); }
         public static void main(String... args) { B b = new C(); b.m(); }
        }

        public interface I {
         public default void m() { System.out.println("I.m"); }
        }

        public abstract class B extends A implements I {
        }

        public class C extends B {
        }

        public class Test {
         public static void main(String... args) { B b = new C(); b.m(); }
        }

        java Test
        Exception in thread "main" java.lang.IllegalAccessError: tried to access method A.m()V from class B

        java A
        Exception in thread "main" java.lang.IllegalAccessError: tried to access method A.m()V from class B

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                • Assignee:
                  acorn Karen Kinnear (Inactive)
                  Reporter:
                  dlsmith Dan Smith
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                  Dates

                  • Created:
                    Updated:
                    Resolved: