A few exception classes such as ExceptionInInitializerError, InvocationTargetException, etc were defined prior to the exception chaining facility and provides the API to get the cause of the exception.  These classes keep its legacy serial field e.g. ExceptionInInitializerError::exception to get the serialization to work on older JDK version.

During the review of JDK-8209553 [1], Peter and Joe suggest to remove this redundant field and implement the serialization using serialPersistentFields, readObject and writeObject. 

It turns out that these redundant fields were removed when the exception chaining support was initially implemented but it got reverted to fix JDK-4385429 since Throwable::setCause rejects any further change as Throwable::cause has been initialized to null.

We can redo the fix for JDK-4385429  by introducing an internal API for these exceptions to set Throwable::cause.

[1] http://mail.openjdk.java.net/pipermail/core-libs-dev/2018-August/054878.html