private int countOccurrences(final String string, char c, int offset) {
        assert string != null : "String must be specified";
        return ((offset = string.indexOf(c, offset)) == -1) ? 0 : 1 + countOccurrences(string, c, offset + 1);
    }
private int countOccurrences ( final String string , char c , int offset ) { assert string != null : "String must be specified" ; return ( ( offset = string . indexOf ( c , offset ) ) == - 1 ) ? 0 : 1 + countOccurrences ( string , c , offset + 1 ) ; }
Returns the number of occurrences of the specified character in the specified {@link String}, starting at the
specified offset

@param string
@param c
@param offset
@return