You may have been using the either the search and Browse portlet or a customized search portlet that made use of the searchandbrowse.jar in portal 7 and or 6.1
Beginning in Portal 8 the search and Browse portlet is no longer available. The inherent features and capabilities of the Search and Browse portlet are now included in the Portal 8 search center portlets and page. Refer to the following pages and documentation for more information
"Starting with Version 8 of WebSphere Portal the Search and Browse
portlet provided with earlier portal versions is no longer available.
The Search Center has been enhanced with advanced search options
previously available in the Search and Browse portlet. Categorization
and taxonomy are no longer available."
So if you are including this jar file in the custom search portlet, that may have to be modified to no longer use this jar ( as this is not available in 8.0)