Multiple JVMs in Windows

Is there a clean way to instal Java 1.5 on a machine that already has 1.4 on Windows?
There are at least four inconsistent ways that applications find the JVM on windows, namely:-
JAVA_HOME (which is not set by the installers)
PATH
system32\java.exe
registry keys
magic hard coded values.
This results in trouble and insconsistencies.
I just hack things but is there some utility that does a "make jvmXXX the default".
Fixing this is long overdue IMHO. Get rid of the registry keys, use JAVA_HOME (which is in the regstry), keep it clean.
Anthony
I always just hack things, but

Just do a Google search for "partition hard drive windows"
You'll find many pages with instructions

Similar Messages

Multiple JVM instances and host computer performance

Hi,
I was wondering if anyone has any facts or sources about how running multiple JVM instances impacts the performance of the hosting computer ?
For example, say you have a long running server process that creates a JVM, how is the performance of the computer impacted if there are five of those processes running, versus ten versus ...
This is a very "it depends" question, but I would like to get an idea of the baseline performance impact that comes with running a JVM, and if there is anyone here that has experience running multiple JVMs I'd appreciate any feedback, whether it's "don't do it, ever" or "no problem!"
Thanks

My only experience with multiple VMs is when I have several Java GUI apps (eclipse, jedit, dbvisualizer) plus tomcat and maybe an ant running on XP.
I don't think that the existence of multiple VMs is in and of itself a problems, but JVMs do tend to be fairly memory hungry, so if you don't have a lot of RAM, you may find yourself crawling along as swapping heats up.
I think that later versions of the Windows VM have started to take advantage of sharing certain core libraries, or pieces of them, so that you don't have as big an incremental memory footprint for additional VMs. I don't know which versions or how much this actually reduces the foot print of second and subsequent VMs though.

Multiple JVMs foe One WL6.1 instance

Hi,
Is it possible to attach multiple JVMs to an instance of WLS6.1
so that all JVMs will be self sufficient in serving client requests....
If it is possible then any pointers in that direction..???
regards
aseem

Each WL server runs in one JVM. If you want to have 4 JVMs, then run 4 WL
servers in one cluster.
"Aseem Rastogi" <[email protected]> wrote in message
news:[email protected]..
currently our App runs on 2 Iplanet App Server ( they are in Cluster)
and each App server has 2 VMs so we we are getting the feel of 4independent
App Servers but Physically we are able to get away with only 2 boxes.
We want to achive the same thing in Weblogic...
thanx
aseem
Michael Reiche wrote:
1) What is your requirement?
2) Clustering.
"Aseem Rastogi" <[email protected]> wrote in message
news:[email protected]..
Hi,
Is it possible to attach multiple JVMs to an instance of WLS6.1
so that all JVMs will be self sufficient in serving client
requests....
>>>
If it is possible then any pointers in that direction..???
regards
aseem

Multiple JVMs

Hi,
Can I run multiple JVMs on the same machie.
If I can, then what are the repurcussions of this.
Spark

I am happily using several JVM's on my Linux box:
1.1.8
1.2.2
1.3.1
1.4.1
The only thing I have to do when switching from one to the other is to adjust PATH.

JVM 1.3.1_06 Solaris 8 (sparc) multiple jvm's crash at the same time

Hi All,
I had multiple jvms crash all at the same time today morning, i was wondering if anyone had any similar issues with 1.3.1_06:
Only a few jvms left an hs_errpid.log: here is the one with the most info:
An unexpected exception has been detected in native code outside the VM.
Unexpected Signal : 10 occurred at PC=0xff02f8f8
Function name=VerifyClassCodes
Library=/www/gmgwh/weblogic/jdk/j2sdk1_3_1_06/jre/lib/sparc/libjava.so
Current Java thread:
at java.lang.Shutdown.halt(Native Method)
at java.lang.Shutdown.exit(Shutdown.java:209)
at java.lang.Terminator$1.handle(Terminator.java:33)
at sun.misc.Signal$1.run(Signal.java:193)
at java.lang.Thread.run(Thread.java:479)
Dynamic libraries:
0x10000 /www/gmgwh/weblogic/jdk/j2sdk1_3_1_06/jre/bin/../bin/sparc/native_threads/java
0xff350000 /usr/lib/libthread.so.1
0xff340000 /usr/lib/libdl.so.1
0xff200000 /usr/lib/libc.so.1
0xff330000 /usr/platform/SUNW,Ultra-Enterprise/lib/libc_psr.so.1
0xfe400000 /www/gmgwh/weblogic/jdk/j2sdk1_3_1_06/jre/lib/sparc/hotspot/libjvm.so
0xff2d0000 /usr/lib/libCrun.so.1
0xff1e0000 /usr/lib/libsocket.so.1
0xff100000 /usr/lib/libnsl.so.1
0xff0d0000 /usr/lib/libm.so.1
0xff1c0000 /usr/lib/libmp.so.2
0xff090000 /www/gmgwh/weblogic/jdk/j2sdk1_3_1_06/jre/lib/sparc/native_threads/libhpi.so
0xff060000 /www/gmgwh/weblogic/jdk/j2sdk1_3_1_06/jre/lib/sparc/libverify.so
0xff020000 /www/gmgwh/weblogic/jdk/j2sdk1_3_1_06/jre/lib/sparc/libjava.so
0xfe7d0000 /www/gmgwh/weblogic/jdk/j2sdk1_3_1_06/jre/lib/sparc/libzip.so
0xfe3e0000 /usr/lib/locale/en_US.ISO8859-1/en_US.ISO8859-1.so.2
0xfe390000 /www/gmgwh/weblogic/jdk/j2sdk1_3_1_06/jre/lib/sparc/libnet.so
0xfe230000 /usr/lib/nss_files.so.1
0xfe160000 /www/gmgwh/weblogic/6.1/sp4/lib/solaris/libmuxer.so
0xfd0e0000 /usr/ucblib/libucb.so.1
0xfd090000 /usr/lib/libresolv.so.2
0xfd050000 /usr/lib/libelf.so.1
0xfafd0000 /app/oracle/product/8.1.7.4/lib/libocijdbc8.so
0xe1800000 /app/oracle/product/8.1.7.4/lib/libclntsh.so.8.0
0xfafb0000 /app/oracle/product/8.1.7.4/lib/libwtc8.so
0xfaf90000 /usr/lib/libsched.so.1
0xfaee0000 /usr/lib/libaio.so.1
Local Time = Wed Jan 19 09:09:31 2005
Elapsed Time = 22367
# The exception above was detected in native code outside the VM
# Java VM: Java HotSpot(TM) Client VM (1.3.1_06-b01 mixed mode)
#

hi there
i would direct my efforts to search for the culprit on who generated the signal (either a INT, TERM or HUP). The crash occurred is just but another side-effect. The VM received a shutdown signal and shld exit. Just that while exiting, it crashed.
There is this bug
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=4904881
Which is pretty rare. I am not sure if you are encountering this bug but if u have a core, a pstack of the core should show > 2 threads with doing the signal shutdown.

How do you get to the "Multiple Item Information" window so I can click "Part of a compilation:?

How do you get to the "Multiple Item Information" window so I can click "Part of a compilation"? When I transfer a CD to iTunes, and the CD has ten tracks, it loads as ten different albums. Also, once this happens, do I have to delete the album and start over or is there a way to merge the albums in iTunes? Using iTunes 10.04.08.

And you've made me remember that using the compilation flag may only work in iTunes if you go into the Songs view, then use View > Column Browser > Show Column Browser and then View > Column Browser > Group Compilations to make sure this line is ticked.
It is also best if View > Column Browser > Use Album Artists is also ticked.
tt2

Hide RANGE option in Multiple Selection Popup window

This is regarding Parameter option.
In parameter variable,i declared NO INTERVALS option
to get only multiple values.
In multiple selection popup window.i want to select only multiple values not RANGE values. so i want to either disable or hide the f7 option.how to do this.
(we have ranges option at Popup window
when u click f7 or complex selection icon at bottom popup window.)
do we have any option to hide this.
Ambichan

hi,
look fm SELECT_OPTIONS_RESTRICT
(here's a docu)
regards Andreas

Server, Multiple JVMs sources

Hi,
i've to create a (web serivce) server application. This application should be ready for clustering or something, if one server isn't fast enough.
I know already some things abou concurrency in Java. I'm no Java newbie. But i don't know how clustering works.
Does it depend on the used JVM?
Or is this for every server (i.e. Tomcat, JBOSS, ...) different?
What are the requirements in the webservice-layer and in the persistance layer?
Any good internet pages/PDFs which discusses this?
Any good books?
I really hope some can help me here, because it's very important for me.
Cheers,
Ingo

I just re-read the guidelines for a clustered web app over the weekend, so I think I've got things straight. Your application will have to be sensitive to two important issues:
1) A class which was previously a singleton may now be instantiated in multiple JVMs. The most obvious side effect of this is that the init() method of any servlet will have a different ServletConfig object passed to it for each JVM it is initialized in. As a result, the application context is no longer a valid place to store information, since the change to the application context is not necessarily propagated to the other JVMs. However, context-params will still be available from all JVMs. Another noticable side-effect is that static variables no longer work as expected (since there may be multiple instances of the same class).
2) The HttpSession object for a given session can only be in existence on one JVM at a time. If the HttpSession needs to migrate to another JVM, then it will be serialized and sent to the other JVM. As a result, adding an object to a session that is not Serializable may result in IllegalArgumentException being thrown. I'm guessing that in the case of a fail-over (node dies unexepectedly) that the HttpSession object is lost.
Brian

Load balancing HTTP requests for an OC4J instance w/multiple JVMs

Hello everyone,
I am using OAS 10.1.3.1 and wish to load balance HTTP requests across an OC4J group of one or more OC4J instances, where each like named OC4J instance may have multiple JVMs or it may just have one JVM.
My mod_oc4j.conf file would contain the following directives :
Oc4jSelectMethod roundrobin:local
Oc4jRoutingMode Static
Oc4JMount /xyz/* xyz
In the degenerate case, I would like to have an OC4J group with a cluster size of one, and have that one OC4J instance have two or more JVMs. I would like to be able to receive a request within my web application, determine that the JVM that has been sent the request is the wrong JVM to process the request, and then call HttpServletResponse.sendRedirect("/xyz"). Then, when the browser receives the HTTP 302 response and issues the subsequent HTTP request, have that request sent to a different JVM than the previous JVM that issued the sendRedirect().
What I have seen is that the subsequent request is sent back to the same JVM that issued the sendRedirect(). I also call invalidate() against the HttpSession prior to calling sendRedirect(), but that does not seem to affect the behavior that I see.
In the full blown case, I would have an OC4J group with a cluster size > 1, and each of those OC4J instances would have at least one JVM. In that case, I wish the sendRedirect() call to allow the subsequent request to be sent to any one of the OC4J instances in the group, and any one of those JVMs within all of those OC4J instances.
Can anyone verify that my mod_oc4j mount directive is appropriate given the select method and routing mode? What else might I need to do to have a chance to have a different JVM respond to the request that results from a sendRedirect()?
Thank you,
Doug

I should clarify that in the full blown environment, the OC4J instances that form a group will each be housed within a separate OAS instance that resides on its own machine.
So ideally, a request could be inbound to say OAS instance 1 on machine A, OC4J instance AA, JVM 2, and I need to force a redirect so that the request can actually be serviced by OAS instance 3 on machine C, OC4J instance AA, JVM 1, and I need to be able to call sendRedirect() against an HttpServletResponse from within a JVM until the subsequent request from the browser, Internet Explorer in my case, is serviced by that JVM.
Thanks,
Doug

Multiple JVM in one server

Hi,
Can we run multiple JVM's on one Solaris server with different applications configured for different JVM's or may be configure a memory intensive application to multiple JVM's.
Please let me know if this works and if there is any documentation for this.
Any help is greatly appreciated.
Thanks

Pione J wrote:
Can we allocate multiple JVM's to one application and i would really appreciate if you can provide me with some literature/suggestions as to how we can do this in Weblogic.Sure, it's called clustering and documentation is available here
http://e-docs.bea.com/wls/docs81/cluster/overview.html
Cheers,
Gerald

Multiple JVM's in one JDK

Hi,
I am curious to know if one JDK spawning multiple JVM's cause any memory/performance issues. The reason being, my company is planning to have number of applications running in one Weblogic Server instance with Multiple JVM's spawning out of same JDK.
Please let me know if this is possible and if there are any negative effects of following this approach.
Any help is greatly Appreciated.
Thanks

JDK installation is a just binary. There is not limit on creating number of JVM runtime process.
There should not be negative effect assuming you have enough capacity on hardware box.

Multiple JVM instances

Dear all,
I am trying to create multiple JVM instances using createJavaVM(...) but I can't do it. When I try to create the second instance, the function returns an error.
Does anybody know about getting multiple JVM instances running??
Thanks in advance,

Hallo,
createJavaVM(...) trys to create a JVM in your current
process, so I am not surprised that you get an error
the second time round, because there is already a JVM
in the process. If you want multiple JVMs, each needs
to be in its own process.
Why do you want to create more than one JVM in your
process? The JVM is multithreadable, and you can start
more than one thread in the JVM. Would that do what
you want?I need multiple instances because my application needs nearly 2Gb of memory and the maximum heap I get is 1700 Mb. I think with multiple instances, I'll get it.
Do you know about getting a bigger heap??
>
David Singleton
[email protected]

Multiple instances in Windows 7. & Adding Administrator in DBA group

i have installed two databases Using DBCA in win7,
& den used set oracle_sid= <old instance name>
then when i said sqlplus / as sysdba
The new instance is starting.. then i tried sqlplus sys/sys as sysdba previous instance password.. it's asking for user name & password.. ??? which i did give & its promting error..
how to deal with multiple instances in windows 7??
& i created a user using net user administrator /active:no ... now i cudn't get to add this user to DBA group?? As while editing tnsnames.ora & etc.. it's saying access denied so created admin user.. now cudn't login to dba user using administrtor profile.. how to add this in dba group ??

Aduke wrote:
i have installed two databases Using DBCA in win7,
& den used set oracle_sid= <old instance name>
Did you create both databases from the same ORACLE_HOME, or did you actually install oracle twice, into separate ORACLE_HOMEs and create your two databases from those separate homes?
then when i said sqlplus / as sysdba
The new instance is starting.. then i tried sqlplus sys/sys as sysdba previous instance password.. it's asking for user name & password.. ??? which i did give & its promting error..
how to deal with multiple instances in windows 7??
& i created a user using net user administrator /active:no ... now i cudn't get to add this user to DBA group?? As while editing tnsnames.ora & etc.. it's saying access denied so created admin user.. now cudn't login to dba user using administrtor profile.. how to add this in dba group ??
Control panel
Computer Management
Local Users and Groups
Users (select your Oracle user)
Properties
Member Of
select orcl_dba
But then, this IS Windows, who knows if your cascade of applets and options is the same as mine? To paraphrase Forest Gump, "My momma always said Windows was like a box of chocolates. You never know what you're going to get."

Running Multiple JVM's on same Server has OutOfMemory - PermGen Errors

I have a scenario where I have 2 application servers. One is running one JVM and the other is running multiple JVMs.
Both are configured with:
-XX:+UseConcMarkSweepGC
-XX:+UseParNewGC
-XX:MaxPermSize=256m
-XX:+CMSPermGenSweepingEnabled
-XX:+CMSClassUnloadingEnabled
The server that is running with only 1 JVM runs stable, however the server that is running multiple JVMs has frequent crashes due to OutOfMemory - PermGen errors. The only other difference is the Heap size. 512mb for each JVM on the app server with multiple instances and 1GB for the server with 1 instance. Is there a relationship/settings that need to be tuned when running multiple JVM's on the same server to avoid this?
Thx

The only other difference is the Heap size. 512mb for each JVM on the app server with multiple instances and 1GB for the server with 1 instance.This isn't a trivial difference. Basically you're saying "When I give the server 1 GB then it's okay but when I give it 512 MB it's not okay." If I saw those symptoms I would take them at face value to start with.
So, turn off one of those servers on the machine that has two. Don't change anything else. Testable prediction: That won't fix your problem.

Multiple Parameter form windows

Hello,
can i open multiple parameter form windows for different reports from forms?
Both forms and reports are 11G.
thanks.

Not sure if you got a fix for this or not yet, but the easy way is to create multiple user parameters entry boxes, kinda like p_item, p_item1, p_item2 and then in the SQL, ITEM=p_item or ITEM=p_item1 etc.

Multiple JVMs in Windows

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