SimpleJsonSerializer sometimes fails to produce correct JSON

[ilya-komlev]

In what version(s) of Spring Integration are you seeing this issue?

6.3.5

Describe the bug

SimpleJsonSerializer has a bug that makes it produce incorrect JSON when dealing with strings that contain $.
For example, when there is a flow with:

• a FileSplitter that has markers=true, markersJson=true
• a file like My $1000000 plan.txt that goes through the splitter

To Reproduce

Run the app from the sample shared below.

Expected behavior

Expecting no IOException.

Sample

https://github.com/ilya-komlev/spring-integration-bug-202410301536