Handling out of memory errors in the compiler can be cumbersome because there are so many places to check for null return values. One possibility to make this easier would be to use C++ exceptions.

Right now HotSpot doesn't use C++ exceptions at all. This stems from the fact that C++ compilers weren't good enough (like 15-20 years ago) to handle C++ exceptions on all platforms. This has changed.

Since HotSpot uses it's own exception throwing mechanism to throw Java exceptions it's very likely not possible to use C++ exception everywhere. Fortunately compilers are well abstracted from the rest of the system and we could use C++ exception only in these modules.