Name: bsC130419 Date: 06/04/2001


java version "1.4.0-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta-b65)
Java HotSpot(TM) Client VM (build 1.4.0-beta-b65, mixed mode)

In an effort to fix bug 4030374, the compiler writers were overzealous, and
created a new bug with -target 1.4. Inner classes and polymorphic methods are
still broken, but now with a VerifyError instead of a NullPointerException.

class A {
  int i;
  abstract class B {
    { foo(); }
    abstract void foo();
  }
}
class C extends A {
  int i;
  public static void main(String[] args) {
    new C().new D();
  }
  class D extends B {
    int i;
    void foo() {
      System.out.println(C.super.i);
    }
  }
}

$ javac C.java
$ java C
Exception in thread "main" java.lang.NullPointerException
        at C.access$001(C.java:38)
        at C$D.foo(C.java:48)
        at A$B.<init>(C.java:34)
        at C$D.<init>(C.java:45)
        at C.main(C.java:42)
$ javac -target 1.4 Foo.java
$ java C
Exception in thread "main" java.lang.VerifyError: (class: A$B, method: <init> si
gnature: (LA;)V) Expecting to find object/array on stack
        at C.main(C.java:42)
$ javap -c A\$B
Compiled from Foo.java
abstract class A. B extends java.lang.Object
    /* ACC_SUPER bit NOT set */
{
    A.B(A);
    abstract void foo();
}

Method A. B(A)
   0 aload_0
   1 aload_1
   2 putfield #1 <Field A this$0>
   5 aload_0
   6 invokevirtual #2 <Method void foo()>
   9 aload_0
  10 invokespecial #3 <Method java.lang.Object()>
  13 return

The culprit is the constructor in A.B. You correctly set this$0 before calling
the super-constructor (line 2), but then incorrectly call method foo() on an
uninitialized object (line 6) before calling the superconstructor (line 10).
The correct code should have lines 6 and 10 swapped.
(Review ID: 125766)
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