In order to make your issue reports as actionable as possible, please provide the following information, depending on the issue type.

Bug report

For bug reports, provide this information, please:

What Debezium connector do you use and what version?

MySQL version 3.3.1-Final and Debezium Embedded Engine.

What is the connector configuration?

<Your answer>

What is the captured database version and mode of deployment?

(E.g. on-premises, with a specific cloud provider, etc.)

<Your answer>

What behavior do you expect?

Given
1. gtidSet1 = UUID1:Range1,UUID2:Range2

2. gtidSet2 = UUID1:Range1

gtidSet1.subtract(gtidSet2) should be UUID2:Range2

What behavior do you see?

`java.lang.NullPointerException: Cannot invoke "io.debezium.connector.mysql.gtid.MySqlGtidSet$UUIDSet.getUUID()" because "other" is null
 
at io.debezium.connector.mysql.gtid.MySqlGtidSet$UUIDSet.subtract(MySqlGtidSet.java:323)
at io.debezium.connector.mysql.gtid.MySqlGtidSet.lambda$subtract$4(MySqlGtidSet.java:126)
at java.base/java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:197)
at java.base/java.util.stream.ReferencePipeline$2$1.accept(ReferencePipeline.java:179)
at java.base/java.util.TreeMap$EntrySpliterator.forEachRemaining(TreeMap.java:3322)
at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:509)
at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
at java.base/java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:921)
at java.base/java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
at java.base/java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:682)
at io.debezium.connector.mysql.gtid.MySqlGtidSet.subtract(MySqlGtidSet.java:127)`
 

Do you see the same behaviour using the latest released Debezium version?

(Ideally, also verify with latest Alpha/Beta/CR version)

Yes

Do you have the connector logs, ideally from start till finish?

(You might be asked later to provide DEBUG/TRACE level log)

<Your answer>

How to reproduce the issue using our tutorial deployment?

<Your answer>

Feature request or enhancement

For feature requests or enhancements, provide this information, please:

Which use case/requirement will be addressed by the proposed feature?

When the source DB being replicated is restarted it acquires a new server UUID. If the connector shutdown before the restart and re-connected after restart, using the subtract method in this class doesn't act as expected.

Implementation ideas (optional)

Add a nullity check in UUIDSet subtract(UUIDSet other) on other.