Github user yanghua commented on the issue:
https://github.com/apache/flink/pull/6231
@pnowojski I have said it is because of the constructor :
```
CompositeTypeSerializerConfigSnapshot(TypeSerializer<?>...
nestedSerializers)
```
used [`varargs ` in JIRA
description](https://issues.apache.org/jira/browse/FLINK-9694), the last
comment in this PR, I just explain it looks like this style.
We added null check and it works fine in our Flink env. So if we do not
process it, in this case, this code is useless:
```
Preconditions.checkNotNull(nestedSerializers);
```
Why we do not check null in the potential nullable context? So what's the
way you think is not ugly and dangerous?
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