If you need to verify at run time whether an object is actually an instance of a particular class, use the instanceof keyword. The instanceof keyword can only be used to verify if the target type in the expression on the right of the keyword is a viable alternative for the declared type of the expression on the left.
If (Reports.get(0) instanceof CustomReport) { // Can safely cast it back to a custom report object CustomReport c = (CustomReport) Reports.get(0); } Else { // Do something with the non-custom-report. }