@ Pure public static String extension ( File filename ) { if ( filename == null ) { return null ; } final String largeBasename = largeBasename ( filename ) ; final int idx = largeBasename . lastIndexOf ( getFileExtensionCharacter ( ) ) ; if ( idx <= 0 ) { return "" ; //$NON-NLS-1$ } return largeBasename . substring ( idx ) ; }
Reply the extension of the specified file .