when installing update of WAS 188.8.131.52 or other fixpack, you might come across this issue:websphere cannot continue the process because folder websphere\appserver\classes is not clean. A file call adminports.jar is there and cannot be removed. The file is save to remove based on this article
but cannot be deleted.
Even though you remove java.exe process manually but the file is still cannot be removed.
Microsoft provides a good tool that you can download called Process Explorer. This tool identifies the open handles associated with the Java process and determines which handles are being opened but not closed. You may want to install this tool so as to provide more helpful clues.
Install this tool, run it and terminate java.exe process
Voila…you can restart the maintenance fixpack update again. ^_^