ClassCastException when casting to the same class

I was getting this problem after adding a dependency to spring-boot-devtools in my Springboot project. I removed the dependency and the problem went away. My best guess at this point is that spring-boot-devtools brings in a new classloader and that causes the issue of class casting problems between different classloaders in certain cases where the new classloader is not being used by some threads.

Reference: A dozer map exception related to Spring boot devtools

I am not quite following your description of the program flow, but usually when you get ClassCastExceptions you cannot explain you have loaded the class with one classloader then try to cast it to the same class loaded by another classloader. This will not work - they are represented by two different Class objects inside the JVM and the cast will fail.

There is an article about classloading in WebSphere. I cannot say how it applies to your application, but there are a number of possible solutions. I can think of at least:

1. Change the context class loader manually. Requires that you can actually get a reference to an appropriate class loader, which may not be possible in your case.

   Thread.currentThread().setContextClassLoader(...);
   

2. Make sure the class is loaded by a class loader higher in the hierarchy.

3. Serialize and deserialize the object. (Yuck!)

There is probably a more appropriate way for your particular situation though.