The test TestJsonSubType#testExpectedJson fails non-deterministically due to non-deterministic ordering of fields. This happens because objectMapper.writeValueAsString() internally uses java.lang.Class.getDeclaredFields method and according to javadocs, 'The elements in the returned array are not sorted and are not in any particular order.'

How to reproduce the issue:

mvn -pl json edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest=TestJsonSubType#testExpectedJson -DnondexRuns=10

Error

[ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.983 s <<< FAILURE! -- in io.airlift.json.subtype.TestJsonSubType
[ERROR] io.airlift.json.subtype.TestJsonSubType.testExpectedJson -- Time elapsed: 0.903 s <<< FAILURE!
org.opentest4j.AssertionFailedError:

expected: "{"name":"Jane","reports":[{"name":"Joe","type":"Programmer"},{"name":"Rachel","type":"Programmer"}],"type":"Manager"}"
but was: "{"reports":[{"name":"Joe","type":"Programmer"},{"name":"Rachel","type":"Programmer"}],"name":"Jane","type":"Manager"}"
at io.airlift.json.subtype.TestJsonSubType.testExpectedJson(TestJsonSubType.java:208)
at java.base/java.lang.reflect.Method.invoke(Method.java:580)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)
at java.base/java.util.ArrayList.forEach(ArrayList.java:1596)

Proposed Solution

Add JsonPropertyOrder to record Manager to specify deterministic order of fields at the time of serialization.
Happy to discuss if you have any questions or need any additional justification/changes from my side.

Airlift contribution check list

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• All automated tests are passing.
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