Name: icC57033 Date: 10/13/99


HotSpot Client 1.3 and HotSpot Server 2.0beta can't start if flag -Xmx1119m is applied.
Korn shell script find_bad_mx.ksh can be used to find upper bound for this flag.
Output for Windows NT 4.0 environment:

$ d:/hotspot/bin/find_*_mx.ksh d:/jdk1.3.0
----------------------- classic ----------------------------
d:/jdk1.3.0/bin/java -classic -Xmx2046m -version
java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-J)
Classic VM (build 1.3.0-J, native threads, nojit)

d:/jdk1.3.0/bin/java -classic -Xmx2047m -version
java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-J)
Classic VM (build 1.3.0-J, native threads, nojit)

d:/jdk1.3.0/bin/java -classic -Xmx2048m -version
Bad max heap size: -Xmx2048m
Could not create the Java virtual machine.

----------------------- hotspot ----------------------------
d:/jdk1.3.0/bin/java -Xmx1118m -version
java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-J)
Java HotSpot(TM) Client VM (build 1.3-K, mixed mode)

d:/jdk1.3.0/bin/java -Xmx1119m -version
Error occurred during initialization of VM
Could not reserve enough space for object heap

$ d:/hotspot/bin/find_*_mx.ksh d:/jdk1.2.2
----------------------- classic ----------------------------
d:/jdk1.2.2/bin/java -classic -Xmx2046m -version
java version "1.2.2"
Classic VM (build JDK-1.2.2-U, native threads, symcjit)

d:/jdk1.2.2/bin/java -classic -Xmx2047m -version
java version "1.2.2"
Classic VM (build JDK-1.2.2-U, native threads, symcjit)

d:/jdk1.2.2/bin/java -classic -Xmx2048m -version
Bad max heap size: -Xmx2048m
Could not create the Java virtual machine.

----------------------- hotspot ----------------------------
d:/jdk1.2.2/bin/java -Xmx1118m -version
java version "1.2.2"
Java HotSpot(TM) Server VM (2.0beta, mixed mode, build G)

d:/jdk1.2.2/bin/java -Xmx1119m -version
Error occurred during initialization of VM
Could not reserve enough space for object heap





####################### find_bad_mx.ksh ###############################
JAVA=$1

maxmem=1024
delta=1024
ret=0
echo '----------------------- classic ----------------------------'
while [ $ret -eq 0 ] ; do
sz=`$JAVA/bin/java -classic -Xmx${maxmem}m -version 2>&1`
ret=$?
if [ $delta -eq 1 ]; then
echo $JAVA/bin/java -classic -Xmx${maxmem}m -version
print "$sz"
echo
fi

if [ $ret -ne 0 ] ; then
if [ $delta -ne 1 ] ; then
maxmem=`expr $maxmem - $delta`
delta=$(($delta/2))
ret=0
fi
else
maxmem=`expr $maxmem + $delta`
fi
done

maxmem=1024
delta=1024
ret=0
echo '----------------------- hotspot ----------------------------'
while [ $ret -eq 0 ] ; do
sz=`$JAVA/bin/java -Xmx${maxmem}m -version 2>&1`
ret=$?
if [ $delta -eq 1 ]; then
echo $JAVA/bin/java -Xmx${maxmem}m -version
print "$sz"
echo
fi

if [ $ret -ne 0 ] ; then
if [ $delta -ne 1 ] ; then
maxmem=`expr $maxmem - $delta`
delta=$(($delta/2))
ret=0
fi
else
maxmem=`expr $maxmem + $delta`
fi
done
####################### END find_bad_mx.ksh ###############################


======================================================================