JDK-8284435 introduced using dedicated filler arrays for ensuring heap parseability instead of simple int arrays. This makes it possible to skip the fillers when writing heap dumps.

These arrays can get large. For example for humongous objects, up to half a region size can be used. They also contain uninitialized memory as content. Additionally, in contrast to the filler objects introduced as well, they cannot be distinguished from other int arrays in the heap dump.

Since they don't provide useful information in a heap dump, they should be skipped, making the dump smaller and the dumping slightly faster.

Removing the filler object too, while possible, seems unnecessary, since they are small, seldomly used and easy to identify.