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https://issues.apache.org/jira/browse/CAMEL-25125?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Claus Ibsen resolved CAMEL-25125.
---------------------------------
Resolution: Fixed
Fixed by https://github.com/apache/camel/pull/27034 (merged to main, 4.23.0).
_Claude Code on behalf of davsclaus_
> camel-mllp - automatic acknowledgement fails with
> ArrayIndexOutOfBoundsException when MSH-2 defines a component separator other
> than '^', so no ACK is sent (regression of CAMEL-22421)
> ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
>
> Key: CAMEL-25125
> URL: https://issues.apache.org/jira/browse/CAMEL-25125
> Project: Camel
> Issue Type: Bug
> Components: camel-mllp
> Reporter: shashank
> Priority: Minor
> Labels: regression
> Fix For: 4.23.0
>
>
> Since CAMEL-22421 (4.15.0), {{Hl7Util.generateAcknowledgementPayload}}
> decides whether MSH-9 has a third component by counting the component
> separators of MSH-9. It finds the start of MSH-9.2 with the component
> separator of the message ({{hl7MessageBytes\[4\]}}, the first character of
> MSH-2), but it counts the components with {{caretPositionsIn}}, which looks
> for a hard-coded '^':
> {code:java}
> final byte componentSeparator = hl7MessageBytes[4];
> ... // msh92start = first componentSeparator in MSH-9
> final String msh9Content = convertToPrintFriendlyString(hl7MessageBytes,
> fieldSeparatorIndexes.get(7) + 1, fieldSeparatorIndexes.get(8));
> final int[] componentIndexesInMsh9 = caretPositionsIn(msh9Content); //
> positions of '^' only
> final int componentDiff =
> componentIndexesInMsh9[componentIndexesInMsh9.length - 1] -
> componentIndexesInMsh9[0];
> {code}
> HL7 v2 recommends the encoding characters "^~\&" but lets MSH-2 define
> others. When the component separator is not '^' and MSH-9 contains no '^',
> the array is empty and the automatic acknowledgement fails:
> {noformat}
> MSH|$~\&|SENDAPP|SENDFAC|RECVAPP|RECVFAC|20260929083646||ADT$A01|MSG00003|P|2.3
> -> java.lang.ArrayIndexOutOfBoundsException: Index -1 out of bounds for
> length 0
> {noformat}
> The exception is not an {{MllpAcknowledgementGenerationException}}, so
> {{MllpTcpServerConsumer.sendAcknowledgement}} does not handle it.
> {{processMessage}} catches it after the route has already processed the
> message, resets the connection and passes the exception to the consumer's
> exception handler. The sender gets no acknowledgement. HL7 senders normally
> resend a message that was not acknowledged, so every resend is processed by
> the route again (a duplicate) and fails in the same way, and the interface is
> stuck on that message.
> With three components the result is wrong instead of an exception: for
> {{ADT$A01$ADT^X}} the ACK has MSH-9 {{ACK$A01$ADT^X}} instead of
> {{ACK$A01$ACK}}, because the '^' in the data is counted and the two '$' are
> not.
> The count also runs on the log-friendly String, which is cut to
> {{logPhiMaxBytes}}: with a {{logPhiMaxBytes}} of 3 or less, even a message
> with '^' fails the same way.
> h3. Reproduction
> {{new Hl7Util(5120, true).generateAcknowledgementPayload(buffer, message,
> "AA")}} with the MSH above, and end to end with an {{mllp://}} consumer with
> the default {{autoAck=true}}: the client's connection is reset and no ACK
> arrives. Reproduced on main three times. The same message with the 4.14.0
> {{Hl7Util}} gives the ACK {{ACK$A01}}. A small formal model (Lean 4) of the
> MSH-9 code shows that every separator other than '^' with an MSH-9 without
> '^' fails, and that counting the MSH-2 separator gives the same result as
> today for '^' and never fails.
> h3. Affected versions
> 4.15.0 and later (4.18.x and 4.22.x LTS, main). 4.14.x does not have the
> change of CAMEL-22421 and is not affected.
> h3. Proposed fix
> Count the component separator of MSH-2, on the message bytes, instead of '^'
> on the log String. For messages with '^', the default, the acknowledgement
> stays exactly the same.
> Duplicate check (2026-09-29): JIRA component camel-mllp since 2025, and
> "mllp" with "separator", "ArrayIndexOutOfBoundsException", "MSH-9" or
> "acknowledgement": only CAMEL-22421 itself. No open pull request touches
> camel-mllp.
> _Filed with Claude Code on behalf of allthingssecurity._
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