About Question com.enthuware.ets.scjp.v6.2.808 :

[ETS User]

I don't think this is true of all JVMs. K&B book specifies that \s and \\s is JVM specific

[admin]

I am not sure about the context in which K&B states that so can't really comment on that. As per the JavaDoc API documentation at http://docs.oracle.com/javase/1.4.2/doc ... ttern.html \s is a whitespace character, so the given answer is correct.