Java ZonedDateTime.toInstant() moves to UTC

I want simply to move an Instant moment to another time zone.

for example

2020-04-08 23:59:59.999 UTC -> to Europe/Sarajevo[UTC+1]

should result at:
2021-04-09 00:59:59.999 UTC

it does not return this

 dateVal.atZone(operatorTimeZone).toInstant()

returns wrong value.

but dateVal.atZone(operatorTimeZone) returns the right value.

unfortunantly I need the response to be Instant.

How can this be fixed?

Thanks and Regards,

What you seem to want to do is to add the timezone's offset at the instant dateVal, to that instant. This can be done by getting the offset and adding directly:

ZoneOffset offset = operatorTimeZone.getRules().getOffset(i);
Instant newInstant = dateVal.plusSeconds(offset.getTotalSeconds());

Another way is to use withZoneSameLocal, though I think this doesn't show the intent as clearly, and is more like a "trick".

Instant newInstant = dateVal
                        .atZone(operatorTimeZone)
                        .withZoneSameLocal(ZoneOffset.UTC)
                        .toInstant();

<hr>

That said, the more I think about this, the more this looks like an XY problem. Representing the result as a ZonedDateTime rather than an Instant is probably what you really should do.