We currently have array_klass() and array_klass_or_null(), where the former can throw exceptions and the latter can not. But they both delegate to:

array_klass_impl(bool or_null, TRAPS)

which combines both the exception-throwing and non-exception-throwing code into one method declared with TRAPS. To make progress with the change of TRAPS to JavaThread (JDK-8252685) we need to separate these code paths into distinct methods.