Check if parameter exists in Expression Language [duplicate]

Answer 1

If you want to check if parameter exists, just test if it is not null, in your case:

Broader explanation:

If you want to check:

• if yourParam exists/ is not null:

• if yourParam does not exist/ is null

• if yourParam is not empty (not empty string and not null)

• if yourParam is empty (empty string or null)

• if yourParam evaluates to 'true'

• if yourParam evaluates to 'false' (string other than 'true')