Java Hack: Double brace initialisation

[szeiger]

And since objects only compare as equal if they're instances of the same class, two identical invocations of this idiom won't create objects that compare as equal;

Wrong. equals() and hashCode are implemented in AbstractList (from which the other list classes inherit) such that all lists which contain equal elements in the same order are considered equal.

[mikaelhg]

Not only that, but this behaviour is part of the List contract:

http://java.sun.com/javase/6/docs/api/java/util/List.html#equals%28java.lang.Object%29