The sentence you refer to is not a general statement. It is part of this paragraph.
A compile-time error occurs if it is impossible to convert the type of either operand to the type of the other by a casting conversion (�5.5). The run-time values of the two operands would necessarily be unequal. This means that the == operator cannot be used between references where one is not a subtype of the other.
This means, for example, that you cannot do something like this.
Since neither FileReader nor
String is a subtype of the other, there is no chance that the objects file and s refer to could be the same.
[ October 25, 2006: Message edited by: Keith Lynn ]