question: public File createNewFolder ( File containingDir ) throws IOException { File result = new File ( containingDir , "New folder" ) ; if ( result . exists ( ) ) { throw new IOException ( "Directory 'New folder' exists" ) ; } if ( ! result . mkdir ( ) ) { throw new IOException ( "Cannot create directory" ) ; } return result ; }
target:  Creates a new folder with the default name "New folder". This method is invoked when the user presses the "New folder" button.