Name: inc88864 Date: 09/22/99



Javac (build 1.3.0-G) does not prohibit use of names like 'val$argv' and
'access$000'. Compiler uses such names for synthetic members, which it creates
to provide inner class semantics. Section "How do inner classes work?" of
Inner Class Specification reads :

" It must be emphasized that these oddly-named "this$" and "val$" fields and
extra constructor arguments are added by the compiler to the generated bytecodes,
and cannot be directly referenced by Java source code. "

After compiling of V.java (below) classfile V$1$Inn.class contains two fields
'val$argv' of type "[Ljava/lang/String;", therefore ClassFormatError occurs
while starting the V class (see trace below).

After compiling of A.java (below) classfile A.class contains two methods
'access$000' of signature "(LA;)I". First of them is non-static so
IncompatibleClassChangeError occurs while starting the A class (see trace below).

Note, that compiler does not allow use of name 'this$0', which also is name of synthetic
member, that compiler add to inner class.
 
Oldjavac and javacs in JDK 1.2.2, 1.2.1 compile the sources without errors.

--------------------------------------=== trace
% java V
Exception in thread "main" java.lang.ClassFormatError: V$1$Inn (Repeative field name/signature)
at java.lang.ClassLoader.defineClass0(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:453)
......
% java A
Exception in thread "main" java.lang.IncompatibleClassChangeError
at A$A2.x(A.java:5)
at A.main(A.java:11)
%
--------------------------------------=== V.java
class V {
// int this$0 = 15;
    interface I {
String s();
    }
    static I iv;

    public static void main( final String argv[] ) {
class Inn implements I {
String val$argv[] = {"+45"};
public String s() {
return argv[0] + val$argv[0];
}
}
iv = new Inn();
System.out.println("iv.s() : " + iv.s());
    }
}
--------------------------------------=== A.java
class A {
    private int X=17;

    class A2 {
int x() { return X; }
    }

    int access$000(A a) { return 22; }

    public static void main( final String argv[] ) {
System.out.println("X (==17) : " + new A().new A2().x() );
    }

}
--------------------------------------===

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