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-Xmine / -Xmaxe

Set the minimum and maximum amounts by which the garbage collector expands the heap.


Setting Default
-Xmine<size> 1 MB
-Xmaxe<size> 0 (unlimited expansion)

See Using -X command-line options for more information about the <size> parameter.


Typically, the garbage collector expands the heap by the amount required to restore the free space to 30% (or the amount specified by -Xminf).

If heap expansion is required:

  • -Xmine forces the expansion to be at least the specified value. For example, -Xmine10M sets the expansion size to a minimum of 10 MB.
  • -Xmaxe limits the expansion to the specified value. For example -Xmaxe50M prevents expansion by more than 50 MB. (-Xmaxe0 allows unlimited expansion.)

For the gencon GC policy, the values apply only to the tenure part of the heap. For the balanced, optthruput, and optavgpause GC policies, these values apply to the whole heap. This option cannot be used with the metronome GC policy (-Xgcpolicy:metronome) because the heap is always fully expanded.

See also