[CentOS] Java/Solr - Could not reserve enough space for object heap.

Hi All.

# cat /etc/redhat-release
CentOS release 6.2 (Final)

# uname -r
2.6.32-220.17.1.el6.centos.plus.x86_64

 # rpm -qa | grep solr
apache-solr-3.5.0-1.5...

I have a solr installation which is invoked:
/usr/bin/java -Xms25g -Xmx25g -DSTOP.PORT=8079 -DSTOP.KEY=mustard
-Dsolr.solr.home=multicore -jar start.jar

After start/when the java process is running:
# free -m
             total       used       free     shared    buffers     cached
Mem:         32093      23975       8118          0        189       5736
-/+ buffers/cache:      18049      14043
Swap:         4095         22       4073

So the machine has 32GB of RAM, and java process needs 25GB to start.
When I make a restart the java process dies and in log:

Jul  4 08:17:27 test.local solr: Error occurred during initialization of VM
Jul  4 08:17:27 test.local solr: Could not reserve enough space for object
heap
Jul  4 08:17:27 test.local solr: [FAILED]

Then a second restart is ok, the process starts and solr is responding.
Have you had such problems? As I think during stop jvm gives back the
memory to the operating system and then during start is requesting 25GB
(can there be a lag in this process?). No other services are running on
this machine.

Best regards,
Rafal.