question: private Instant convertTimestamp ( long timestamp ) throws FormatParseException { if ( timestamp == 0 ) { return Instant . ofEpochSecond ( timestamp ) ; } int digits = ( int ) ( Math . log10 ( timestamp ) + 1 ) ; if ( digits != 10 && digits != 13 ) { throw new FormatParseException ( "Expected a timestamp length of 10 or 13, found " + digits + " ('" + timestamp + "')" ) ; } boolean secondResolution = digits == 10 ; return secondResolution ? Instant . ofEpochSecond ( timestamp ) : Instant . ofEpochMilli ( timestamp ) ; }
target:  Converts the timestamp to an Instant. <p> Supports 10 digit timestamps (second resolution) and 13 digit timestamps (millisecond resolution).