Getting Attribute Values stored within application scope

I am storing unknown number of attribute names and values from user within application scope. There are some application specific attributes within application scope ( So when you type Enumeration en = getServletContext.getAttributeNames(); , it contains some other attributes that you haven't set but system specific). My question is how can i get those attribute values that i receive from users which i store within application scope (without application specific attributes which contains system information etc) ?

Scenario could be like this: User input:

hello

Output:

hello

User input: good times

Output:

hello

good times

User input:

bad times

output:

hello

good times

bad times .. ..

P.S It is essential to store those input values within application scope.