ArgumentMethodArgumentResolver and QueryByExampleDataFetcher are not thread safe

[dugenkui03]

Note: Due to its reliance on PropertyEditors, SimpleTypeConverter is not thread-safe. Use a separate instance for each thread.
https://github.com/spring-projects/spring-framework/blob/68757073b0cf69c41d5c17e8abdffbc388cdbabe/spring-beans/src/main/java/org/springframework/beans/SimpleTypeConverter.java#L26

It seems that all the concurrent operations in ArgumentMethodArgumentResolver share one SimpleTypeConverter, as well as QueryByExampleDataFetcher.

[rstoyanchev]

It does look like a possible issue. I've scheduled it for M6 to have a closer look.

[mp911de]

FWIW, QueryByExampleDataFetcher and Spring Data repositories are generally thread-safe as a repository invocation doesn't change any internal state.