-Xms / -Xmx
These Oracle® HotSpot™ options set the initial/minimum Java™ heap size, and the maximum heap size respectively. These options are recognized by the OpenJ9 VM.
- If you set
-Xmx, the OpenJ9 VM fails with the message
-Xms too large for -Xmx.
- If you exceed the limit set by the
-Xmxoption, the OpenJ9 VM generates an
If you are allocating the Java heap with large pages, see also -Xlp and More effective heap usage using compressed references.
You can also use the
-Xmo option (not supported by the balanced garbage collection policy):
If the scavenger is enabled,
If the scavenger is disabled,
||Set initial heap size||8 MB|
||Set maximum heap size||25% of available memory (25 GB maximum)|
- Heap starts at 2 MB and grows to a maximum of 64 MB.
- Heap starts at 100 MB and never grows.
- Heap starts at 50 MB and grows to the default maximum.
- Heap starts at default initial value and grows to a maximum of 256 MB.