What is jsp expression language?

The Expression language represents some expression. It has following features,
-Deffered expressions which can be evaluated at different stages of page life cycle.
-Method expressions which can invoke the methods.
-Expressions that can set the data of external objects and get the data.
-A flexible mechanism to enable the customization of variable and property resolution for EL expression evaluation.
By use of expression language we can write script free jsp pages.
Expression language is something like ${expr}

We can write as ${firstthing.secondthing}
firstthing can be a EL implicit language(Map) or attribute.
Secondthing can be: if the first thing is attribute(bean class) then the second thing is the bean property stored in any scope(page,session,request,application). If the first thing is an implicit object then the second thing is a map key(why map key see next question).
If person is a bean class and there is an attribute “name”. Then how to get the name using EL, ${Person.name} or ${person[“name”]}