question: public static String randomAlphanumerical ( final int len ) { final StringBuilder sb = new StringBuilder ( len ) ; for ( int i = 0 ; i < len ; i ++ ) { sb . append ( AB . charAt ( random . nextInt ( AB . length ( ) ) ) ) ; } return sb . toString ( ) ; }
target:  Generates a random alphanumerical String of the given length. The used characters are:<br> <br> 0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ