I have an outputText field for which I write a condition in the rendered attribute. The condition is for comparing the length of the string with so
You have to use gt and lt operators.
Check out JavaServer Faces Expression Language Intro from Sun/Oracle. Precisely the Operators section.
rendered only accepts EL expression.
subsAlertsHelper.personEmail.length() is incorrect.
On the personEmail object, add a method getLength() witch returns the length
public int getLength(){ return this. length();}
Modify :
rendered="#{subsAlertsHelper.personEmail.length >20}"