Like any other engineer, every year or so, I need to solve a time zone conversion bug. Combining the results from a quick Google search will usually solve any new problem. On the rare occasion that it doesn't, I'll post my solutions here.

Epoch is supposed to be UTC. But not every company follows that rule. Sometimes a company will break that rule before exposing their API to customers. Then, when the mistake is pointed out, they are loath to change it because other customers rely on the error being consistent. That is how I ended up needing to convert epoch from Eastern time to UTC in Golang. Here's how I did it.

func convertToRealEpoch(unix_timestamp uint64) uint64 { 
    fmt.Println(unix_timestamp) 
    t := time.Unix(0, int64(unix_timestamp) * 1000) 
    fmt.Println(t) 

    loc, _ := time.LoadLocation("America/New_York") 
    t2 := time.Date(t.Year(), t.Month(), t.Day(), t.Hour(), t.Minute(), t.Second(), t.Nanosecond(), loc) 
    fmt.Println("t2", t2) 

    l, _ := time.LoadLocation("UTC") 
    real_epoch := t2.In(l).UnixNano() / 1000 
    fmt.Println(real_epoch) 

    return uint64(real_epoch)
}

If you're using joda.org.time.DateTime and want to convert for Timezone, use this method:

private DateTime convertJodaTimezone(DateTime dateTime, String srcTz, String destTz) {
    LocalDateTime date = new LocalDateTime(dateTime);
    DateTime srcDateTime = date.toDateTime(DateTimeZone.forID(srcTz));
    DateTime dstDateTime = srcDateTime.withZone(DateTimeZone.forID(destTz));
    return dstDateTime.toLocalDateTime().toDateTime();
  }

Nobody else on my Google search results had pulled it out into a separate method, so I thought I'd put this out there for anyone else having the same problem.