Derrick2000 opened a new pull request, #2147:
URL: https://github.com/apache/cxf/pull/2147

   Dear Maintainers,
   
   Our [Nondex](https://github.com/TestingResearchIllinois/NonDex) tool has 
detected a potential flaky test at 
`org.apache.cxf.tools.wadlto.jaxrs.JAXRSContainerTest.testThrows`. This 
flakiness is caused by an ordering issue when iterating over a HashMap and 
using assertArrayEquals in the unit test.
   
   The issue with map.entrySet() lies in the fact that HashMap does not 
guarantee any specific iteration order for its entries. This lack of 
deterministic ordering introduces an element of randomness to the test 
execution, causing unreliable test results. Here are some reasons why this can 
happen:
   
   Non-Deterministic Ordering in HashMap: HashMap inherently has no fixed order 
for its elements, and this order can change across different runs or Java 
versions. As a result, iterating over map.entrySet() may yield entries in a 
different sequence each time, depending on factors like hash code distribution 
and hash collisions.
   
   Use of assertArrayEquals: The assertArrayEquals method in JUnit (and similar 
testing frameworks) checks for exact order in array elements. When the test 
iterates over a HashMap and collects entries into an array for comparison, any 
change in iteration order will cause assertArrayEquals to fail, even if the 
contents of the array are logically the same.
   
   Impact on Test Consistency: This ordering inconsistency means that the test 
can pass or fail unpredictably, depending on the iteration order of the 
HashMap. Such flaky behavior can cause false negatives, where a test fails not 
because of a bug in the code under test, but due to the non-deterministic 
nature of HashMap ordering.
   
   Concurrency and Threading Issues: If there are multiple threads accessing or 
modifying the HashMap during the test (intentionally or unintentionally), this 
can further exacerbate flakiness. Any modification to the map’s state while 
iterating can lead to ConcurrentModificationException or silent changes in 
iteration order.
   
   Thus, we have suggested:
   1. HashMap to LinkedHashMap
   2. assertArrayEquals to assertEquals with Set collections


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