Thank you - very nice explanation. I am suprised that the last option with the null did not work. I found this on the sun site regarding the empty operator and the EL
The language offers the following operators (parentheses here are used only for grouping):
binary logical operators
(<, <=, ==, >=, >, lt, le, eq, ge, gt)
binary arithmetic operators
(+, -, *, /, div, %, mod)
indexing operators
(.) and ([])
(equivalent) unary negation operators
(!, not)
arithmetic unary minus
(-)
(empty) operator, which evaluates to true if the expression evaluates to null, or evaluates to a container object that contains no items. ternary operator for simple if-then-else
(?
