question: public boolean isNumericalRun ( String pin ) { final int len = pin . length ( ) ; int prevDigit = Character . digit ( pin . charAt ( 0 ) , 10 ) ; int prevDiff = Integer . MAX_VALUE ; boolean isRun = true ; for ( int i = 1 ; isRun && i < len ; i ++ ) { final int digit = Character . digit ( pin . charAt ( i ) , 10 ) ; final int diff = digit - prevDigit ; if ( prevDiff != Integer . MAX_VALUE && diff != prevDiff ) { isRun = false ; } prevDiff = diff ; prevDigit = digit ; } return isRun ; }
target:  Tests the string to see if it contains a numeric run. For example, "123456", "0000", "9876", and "2468" would all match.