Getting cannot convert object to ArrayList error when retrieving ArrayList from HttpSession

Question

I have saved an ArrayList to the session object. I am trying to retrieve it using

sriList = session.getAttribute("scannedMatches");

I am getting the compile time error "Cannot convert from Object to ArrayList". How can I get my ArrayList back from the session object.

Answer 1

The HttpSession#getAttribute() method returns java.lang.Object:

public java.lang.Object getAttribute(java.lang.String name)

Did you try to cast the returned object?

sriList = (ArrayList)session.getAttribute("scannedMatches");

Answer 2

You have to cast it.

sriList = (ArrayList)session.getAttribute("scannedMatches");

Answer 3

try this:

Object scannedMatchesObj = session.getAttribute("scannedMatches");
if ( scannedmatchesObj instanceOf List ){
    sriList = (ArrayList)scannedMatchesObj;
    //Do your stuff...
}