To store mappings of fancy pair characters . For example 6 is paired with 9 and 9 is paired with 6.
Map < Character , Character > fp = new HashMap < Character , Character > ( ) ; fp . put ( '0' , '0' ) ; fp . put ( '1' , '1' ) ; fp . put ( '6' , '9' ) ; fp . put ( '8' , '8' ) ; fp . put ( '9' , '6' ) ;