Answer by  
                                                                                          gigo (1706)
                                                            
                          
                          
                                                           The ending ". jdk" is the juno's backup file. Juno is a Firefox plugin. You can see it in your software list. To check that, go to the "add/remove installed software" entry. Thus it is a backup file you should be able to remove it, if firefox isn't running.