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  1. JDK
  2. JDK-4122596

valid cast to interface array type throws ClassCastException

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    • Subcomponent:
    • CPU:
      sparc
    • OS:
      solaris_2.5.1

      Description



      Name: laC46010 Date: 03/24/98


      JDK1.2beta3N fails to pass the JCK-114a test case: lang/CONV/conv083/conv08303/conv08303.html
      Particularly, legal attempt to cast an array of a class type to an interface array type
      throws java.lang.ClassCastException exception even if the class implements that interface.

      See an reduced example below.

      Note that when x[0] is initialized (uncomment "//x[0] = new C3();")
      test works fine and ClassCastException is not thrown.

      ------------------------- run --------------------------
      > java -fullversion
      java full version "JDK-1.2beta3-N"
      > javac -d /tmp conv08303.java
      > java -verify conv08303
      x:[LC2;@c084138e
      x[0]:null
      java.lang.ClassCastException: java.lang.Object
      at conv08303.main(conv08303.java:16)

      ------------------------- run with init-ed x[0] -------
      > javac -d /tmp conv08303.java
      > java -verify conv08303
      x:[LC2;@c0842f9c
      x[0]:C3@c08c2f9c
      v:[LC2;@c0842f9c

      ------------------------- conv08303.java --------------------------
      interface I1 { int a = 777; }
      interface I2 extends I1 { int b = 33; }
      class C1 implements I2 { int i; }
      class C2 extends C1 implements I1 { float f; }
      class C3 extends C2 { double d; }

      public class conv08303 {
      public static void main(String args[]) {
      I2 v[];
      I1 x[];

      x = new C2 [5];
      //x[0] = new C3();
      System.out.println("x:"+x);
      System.out.println("x[0]:"+x[0]);
      v = (I2 []) x;
      System.out.println("v:"+v);
      }
      }
      -----------------------------------------------------------------------------

      ======================================================================

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            Assignee:
            sliangsunw Sheng Liang (Inactive)
            Reporter:
            leosunw Leo Leo (Inactive)
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