this particular issue is not new, so it isn't necessarily related to sdk35. the report describes jdk.internal.misc.Unsafe.park. it is a kind of "wait" used in conjunction with a thread pool.
my understanding is that you cannot call jdk.internal.misc.Unsafe.park yourself, so if you're coding in b4a, then the use of thread pools is probably beyond your control. even if you are coding in java and use the executors class for running background threads, jdk.internal.misc.Unsafe.park is used by the system to make sure things don't get out of hand.
if the system has called jdk.internal.misc.Unsafe.park when running a thread, and it times out waiting for that thread or if the thread is interrupted, this can cause an anr if the main thread has been waiting for some background thread (which has been run using the executors class). if you google "jdk.internal.misc.Unsafe.park", you'll see it is a known issue. network problems are an example of what might cause the exception.