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Viewing the Heap Snapshot at the End of the Recording Information

When the JRA stops recording, it calculates the value of the committed heap size, which is how much heap the application has been allowed to use. This size can be set by the -xmx flag.

The memory that is considered large object chunks, is the total amount of memory on the heap that the Java application is allowed to use for large objects (64 KB to 512 kB).

The memory for the pinned object chunks is the amount of memory that is occupied by pinned objects. A pinned object is both referenced by another object in the application and is not allowed to be moved for compaction purposes, for example, i/o buffers that are accessed from native methods (native i/o). The number of pinned object chunks shows a value of how many object that are pinned.

Dark matter is memory that is free, but cannot be used due to the physical layout of the memory chunk (i.e. it might be too small for the application to allocate). Dark matter can cause fragmentation on the disk.

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