-Xmns

Sets the initial size of the new area to the specified value when using -Xgcpolicy:gencon.

-Xmns<size>
By default, this option is set to 25% of the value of the -Xms option. This option returns an error if you try to use it with -Xmn. You can use the -verbose:sizes option to find out the values that the VM is currently using. If the scavenger is disabled, this option is ignored.