Class Data Sharing : what the definition of JSA ?

Hi everybody,
I read the article on Class Data Sharing (http://java.sun.com/j2se/1.5.0/docs/guide/vm/class-data-sharing.html) and they speak about the file classes.jsa
I'm curious and I would like to know the definition of JSA extension.
Maybe JavaSharedArchive ?
google say me that JavaSharedArchive is used by Mac but not by JRE1.5 !
Thanks for your explications !
Obelix

Since the point of using a hotspot is to provide data to other devices, the answer to your question is YES.

Similar Messages

Class Data Sharing in Java 5

Hi All,
I am looking at porting over our current Java application from Java 1.4.2 to Java 1.5.
One of the main reasons is because of the CDS facility in Java 1.5.
Running the same app, one on 1.4.2 and the other on 1.5, on 1.5 it uses about 20% more memory !!!!
This application involves 3 JVM's running communicating via RMI.
When I start each of the applications with -Xshare:on, the first starts fine, indicating it is using CDS,
(-showversion parameter will indicate sharing), but then the next two wont start giving an error indicating
the shared archive cannot be accessed.
Before I started the apps I manually created the shared archive using the call java -Xshare:dump which
places the classes.jsa file in the directory jre/lib/i386/client/classes.jsa
I am running an Intel Solaris platform.
Any ideas why this isnt working ?

ok, I have some more information after doing more investigation...
Here is the bug which I submitted to Sun...
FULL OS VERSION :
SunOS con1 5.8 Generic_108529-29 i86pc i386 i86pc
A DESCRIPTION OF THE PROBLEM :
I am running an application with 3 JVM's. I have manually enabled Class Data Sharing using the command java -Xshare:dump. This seems to work fine.
When I start the first JVM with the command line option -Xshare:on it seems to start fine and indicates "sharing" when I print out -showversion.
Then when I start any subsequent JVM's with -Xshare:on AND the -Xmx5m parameter I receive the following error:
An error has occured while processing the shared archive file. Unable to reserve shared region. Error occurred during initialization of VM Unable to use shared archive.
It seems to work fine if I dont set the maximum heap size.
THE PROBLEM WAS REPRODUCIBLE WITH -Xint FLAG: No
THE PROBLEM WAS REPRODUCIBLE WITH -server FLAG: No
STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Try to execute a JVM with class data sharing on, then try it again with class data sharing on, AND trying to set the maximum heap size.
EXPECTED VERSUS ACTUAL BEHAVIOR :
It should still allow CDS.
ERROR MESSAGES/STACK TRACES THAT OCCUR :
An error has occured while processing the shared archive file. Unable to reserve shared region. Error occurred during initialization of VM Unable to use shared archive.
REPRODUCIBILITY :
This bug can be reproduced always.
The error only occurs when using Xshare AND Xms<NUMBER>m as parameters !

Class Data Sharing for User Defined Classes

i am using jdk 5.0 . JDK 5.0 supports class data sharing for system level classes. Is there any way a class data sharing be done for a user defined class?

Samantha10 wrote:
Is this class data sharing possible for user defined classes also? i have a singleton class which i am invoking through a script. The script has been scheduled to run every 1 sec . Since it is being invoked every 1 sec hence the singleton pattern is failing . Hence if the this class data sharing is possible then the singleton pattern can be made applicable.If you have a single process and you have a single class loaded by two different ClassLoader instances
in some respects they will be two different classes
if (class1 instanceof class2.getClass())returns false.
This is not the case for Java core classes because they are always loaded by the SystemClassLoader.
You write you
have a singleton class which i am invoking through a script. What approach to you use to invoke the singleton?
I am trying to figure out if you launch a new JVM every second...
Maybe you can use Nailgun.

Javaagent and class data sharing with Java 6.0

Hi,
I'm trying to use instrumentation (using the -javaagent) but
I noticed that when I run the my application with JDK 1.6 it loads all system
classes from the "shared objects file" and the transformer has no chance to run.
With JDK 1.5 it works fine, as well as in debug mode of JDK 1.6.
Is this normal or it is a bug? If it is normal, how should I instrument the system classes?
Thanks in advance,
Genady

I just found that the reason it was working for me with JDK 1.5 is that my classes.jsa file was corrupted for some reason.
So the behavior is consistent for both JDK 1.5 and 1.6.
I also found that if I add
Can-Redefine-Classes: true to the manifest (even if I don't do any class redefinitions) it causes the class data sharing to be disabled.
This workaround is good enough for me.
Genady

Class Data Sharing

I am trying to benchmark memory footprint using the class data sharing feature on Solaris8 and Solaris9.
I wrote a small sample java program MyApp.java as follows,
     import java.lang.*;
     public class MyApp {
          public static void main(String[] args) {
               System.out.println("Java VM Version Number = " + System.getProperty("java.vm.version"));
               long maxMem = Runtime.getRuntime().totalMemory();
               System.out.println("Total Memory in bytes= " + maxMem);
               long freeMem = Runtime.getRuntime().freeMemory();
               System.out.println("Free Memory in bytes= " + freeMem);
               long memUsed = maxMem - freeMem;
               System.out.println("Memory Used in bytes= " + memUsed);
               long t1 = System.currentTimeMillis();
               for (int i = 0; i < 3; i++)
                    try
                         System.out.println("iteration count = " + i+1);
                         Thread.sleep(1000 * 60);
                         long t2 = System.currentTimeMillis();
                         long t3 = t2 - t1;
                         System.out.println("time elapsed in milliseconds = " + t3);
                    catch (InterruptedException e)
     $JAVA_HOME = /packages/sun/j2sdk1.5.0_02/jdk1.5.0_02/
     I ran it both the machines with the following options
     1)     $JAVA_HOME/bin/java �client �Xshare:on MyApp
     2)     $JAVA_HOME/bin/java �client �Xshare:off MyApp
     I ran the pmap command with �x option to get the readings
     A) Solari8:
          VM Option     RSS          Shared Mem          Private Mem
          Xshare:on     53584KB     50600KB          2984KB
          XShare:off     11456KB     7808KB          3648KB
          JDK1.4     29736KB     26392KB          3344KB
     B) Solaris9:
          VM Option      RSS          Anonymous mem
          Xshare:on     49384KB     3048KB
          Xshare:off     48576KB     3704KB
          JDK1.4     33656KB     2856KB
     These numbers repeat for multiple instances of the same application.
     I do not see the expected memory savings.
     I am trying to find out if I am missing any step in the process of using
     Class Data Sharing feature of JDK1.5
Thanks!!

Samantha10 wrote:
Is this class data sharing possible for user defined classes also? i have a singleton class which i am invoking through a script. The script has been scheduled to run every 1 sec . Since it is being invoked every 1 sec hence the singleton pattern is failing . Hence if the this class data sharing is possible then the singleton pattern can be made applicable.If you have a single process and you have a single class loaded by two different ClassLoader instances
in some respects they will be two different classes
if (class1 instanceof class2.getClass())returns false.
This is not the case for Java core classes because they are always loaded by the SystemClassLoader.
You write you
have a singleton class which i am invoking through a script. What approach to you use to invoke the singleton?
I am trying to figure out if you launch a new JVM every second...
Maybe you can use Nailgun.

How to Create BO in BOPF as to hold 3 different Nodes as Transient and Data sharing between the 3 Nodes ?

Hi All,
My requirement :
I have to create a FBI OVP Application, Displaying Search UIBB in the first Section .(Fetches Data from Standard Table)
Below this search UIBB I have to create a List UIBB (Name it as LIST_1) in the Second Section to display Search Result.(This List UIBB has to Tool Bar Actions like 'Delete' & 'MOVE' . user select a record from the list and click on delete action, Delete action has to remove the Record from the list ).
Below this List UIBB we have another List UIBB (Name it as LIST_2) which Holds the Records Moved from the LIST_1.(User selects a record in LIST_1 and Clicks on action 'MOVE' the selected record in the LIST_1 has to be Removed and it should be place in the LIST_2 ).
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Create LIST_1 and LIST_2 as transient nodes ---> Propose Names for Data structure, combined structure, combined Table type. Provide fields in the data type and Generate Dictionary Objects.
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Question 2) How to Code to move a Record from the LIST_1 to LIST_2 based on user selection in the LIST_1 in MOVE Action ?
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Question 4) If i Create # different BO How can i achieve this Functionality ?
Please Guide me with Your valuable Suggestions.
Thanks in Adv.
Thanks,
Kranthi Kumar.

Hello Kranti,
As I understand , you have all the required data in non BO existing standard tables. You now want to represent this data as a business object. What you need is a BO wrapper on this existing data , and a controller object would be one way to achieve this ( in theory ). Or you can create a Business Process Object/Master Data Object that acts as a BO wrapper ( with its own buffer implementation ) on top of existing data/APIs , see the standard Business Process Object BO /BOFU/BASIS_APPLICATION_LOG as an example. The Master Data Object /BOFU/BUSINESSPARTNER is another example.
Question 1) How to code to delete a Record from LIST_1 in DELETE Action ?
There is nothing to be done here. The underlying data source for the list is a BO node and the standard Delete action that you get as part of regular CRUD for a BO node will do the job. However note that this delete just deletes the record from the buffer, if this now needs to be translated to an actual delete in the standard table then you need to handle that.
There are two ways to handle the actual update to the table based on how you consume the data from the table. You can do the update within a determination set to Before Save (Before writing data). Or , you can create your own buffer implementation and handle your data manipulation there.
Question 2) How to Code to move a Record from the LIST_1 to LIST_2 based on user selection in the LIST_1 in MOVE Action ?
Add the record to the underlying node for List_2 and remove the record from the underlying node of List_1.Again , this is just buffer data manipulation , the standard tables are not touched , you will need to handle that.
Question 3) Is this Possible to Handle all the 3 nodes in my requirement in a single BO or I Should Create 3 different BO as in my requirement the 3 nodes are independent and in the BO it uses KEY and Parent_Key relation with the SUB Node, Is this possible to handle all the 3 independent nodes in single BO ?
Your BO design depends upon your requirements/use case/functionalities. Is the data related and can be defined as constituent of a single business entity ? If yes , then it should ideally be a single business object. In short , let your functionality decide the scope of your business object. Technical considerations should be secondary.
In addition , remember that too many Business Objects will create a performance overhead.
The use case that you provide is technical and it does not give me enough info to advise on the scope of the business object(s) you will need to create. From a technical perspective , handling 3 nodes in the same business object to address your use case is very much possible.
Question 4) If i Create # different BO How can i achieve this Functionality ?
I will indulge in this question from a point of technical feasibility. When you have multiple BOs and you want to establish a relationship between them , this is achieved by using Business Object Representation nodes. Business Object Representation nodes enable cross BO associations that establish a relationship between a node of the source BO with a node of the target BO.
Regards,
Indranil.

Maximum character limits for data types under the Definition tab in Outbound Dialer Import Rule configuration.

Hello,
We're running an outbound SIP dialer under UCCE 8.5(4). The need has come up to allow more than 10 characters for the first name field under the Definition tab in the import rule configuration section, however, it seems that 10 characters is the upper limit. The reason for wanting to do this is that we're seeing a large number of calls fail to import because the members first name is larger than 10 characters, for example, an import record with a first name of Maximillian will fail. The idea was presented to simply shorten the member name in the event it exceeds 10 characters. However, the concern is that this will cause the agent to mispronounce the members name when they are connected on the phone during initial greeting. For example, Maximillian now becomes Maximillia. Has anyone ever run into the need to do this? Is there a known workaround? Any ideas would be greatly appreciated.
Regards,
-Mike

Mike,
Are you certain that you're trying to increase the value of the correct field? When you go into your Import Rule > Definition tab > highlight the FirstName field name and click Modify... What you should see for Field length is 1-255. You can easily increase the number of character to over 10.

How to use dates/times in the definition of local fields?

Hello!
I have few tough questions for which I haven't found an answer. I hope someone is capable to help me.
1. Is there a transaction to search tables if we know the field?
2. I'd like to define a local field and need to use dates in the calculation function. So basically I need to calculate the lean-time from the date of the purchase order (field BSTDK) to the date of the final delivery (field PLIFTS) and the result should be displayed in weeks. How can I do this? Or can I?
3. Can I use the local fields further in my calculations?
Thank you in advance!
Maria Kangasniemi

Hi,
1. Is there a transaction to search tables if we know the field?
Tcode: SE84
2. I'd like to define a local field and need to use dates in the calculation function. So basically I need to calculate the lean-time from the date of the purchase order (field BSTDK) to the date of the final delivery (field PLIFTS) and the result should be displayed in weeks. How can I do this? Or can I?
Doing some calculation you can define it.
3. Can I use the local fields further in my calculations?
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After restore there was this MYSTERY DATA! What the ****?

When I first got my new mac I wanted to test out some games, so I went through boot camp to install XP and well I didn't read the instructions first (yes my fault) so I had it set to format the drive to FATS when in the instructions it wanted NTFS. Don't worry, it is all working after I restored the system to all mac then (finally) found the instructions and used boot camp again. But the second time I was looking at the partition section of boot camp and saw there was about 5 gigs of new data! hmm... thats odd! Any one els see this?? I know its only 5 gigs but Im planning on repartitioning the drive again and don't want to loose more space! allrighty, well thanks for your time!

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Class Data Sharing (CDS) and memory analys with pmap

Hi everybody,
I read that CDS can decrease the memory footprint by sharing some librairies.
I did some tests on PowerPC board and embeddedJVM 1.5 with 128Mo ROM
I wrote a HelloWorld with a sleep(10) and see the results :
# java -Xshare:off HelloWorld
mapped:   172568 KB writable/private: 165708 KB shared: 32 KB
# java -Xshare:on HelloWorld
mapped:   201112 KB writable/private: 188604 KB shared: 5680 KBThe shared memory increase, normal...
The memory mapped and writable/private increase, I thought that memory will decrease...
so, where is the benefits ?
And the mapped memory is > to board memory ! why ?
thanks for your help
Obelix

somebody can do this tests please :
Write a HelloWord.java with a sleep() of 10s and execute this scripts :
#!/bin/sh
java -version >> testsCDSoff.txt 2>&1
java -Xshare:off HelloWorld &
PID=$!
sleep 2
pmap -d $PID | grep mapped >> testsCDSoff.txt
java -Xshare:off HelloWorld &
PID=$!
sleep 2
pmap -d $PID | grep mapped >> testsCDSoff.txt
java -Xshare:off HelloWorld &
PID=$!
sleep 2
pmap -d $PID | grep mapped >> testsCDSoff.txtand
#!/bin/sh
java -version >> testsCDSon.txt 2>&1
java -Xshare:on HelloWorld &
PID=$!
sleep 2
pmap -d $PID | grep mapped >> testsCDSon.txt
java -Xshare:on HelloWorld &
PID=$!
sleep 2
pmap -d $PID | grep mapped >> testsCDSon.txt
java -Xshare:on HelloWorld &
PID=$!
sleep 2
pmap -d $PID | grep mapped >> testsCDSon.txtand then dump testsCDSoff.txt and testsCDSon.txt here :D
Look at mines :
testsCDSoff.txt
java version "1.5.0_06"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)
Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode, sharing)
mapped: 237220K    writeable/private: 186972K    shared: 44740K
mapped: 237220K    writeable/private: 186972K    shared: 44740K
mapped: 237220K    writeable/private: 186972K    shared: 44740K
testsCDSon.txt
java version "1.5.0_06"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_06-b05)
Java HotSpot(TM) Client VM (build 1.5.0_06-b05, mixed mode, sharing)
mapped: 265808K    writeable/private: 210252K    shared: 50048K
mapped: 265808K    writeable/private: 210252K    shared: 50048K
mapped: 265808K    writeable/private: 210252K    shared: 50048Kwhere is the benefits ? I did an error somewhere or I don't understand CDS ?

A Generic Class is Shared by all its Invocations

hello all,
i am not understanding what this means
all instances of a generic class have the same run-time class, regardless of their actual type
i am taking this to mean that no matter how many instances of list i create underneath it all 1 class is actually holding all my data for all instances. is this correct?
maybe i am not clear on the definition of a runtime class.
how does this affect my programming? will calling static methods on one instance affect the others?
i am confused
thanks
ed

i am not understanding what this means
all instances of a generic class have the same
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i am taking this to mean that no matter how many
instances of list i create underneath it all 1 class
is actually holding all my data for all instances. is
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i am confusedHope you�re not anymore.
Cheers
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We have to add about 900 email address to cost center master data. Whats the best way of achieving this?
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Hello Ravi,
I do not see any email ID field in the cost center master. You may insert the ID in one of the available address fields. You may use LSMW or BDC to upload the same or even mass processing transaction KS12.
BR // SG

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Hi All,
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Created a XML data definition which contains the SQL query in its CDATA section & p_rundate (DATE) parameter.
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Looking for any available solution for the same.
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Hello:
I have been coding in Flash Builder Burrito and publishing to my Xoom for a few weeks. All of a sudden at the end of the day I'm getting this compiler error which says:
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Please help!

Wow, some really strange behavior.
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Then I uncomment the new section which contains the following code:
lineStyle(1.0,0x8ea4bf);
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var line_commands:Vector = new Vector();
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I did figure out how to fix this with out reinstalling. I have to delete the project from my list (making sure to comment out the code above), then re-launch FB Burrito, then re-import the project and it works.
This is way nuts! I dont understand ... am I crazy?

Class Data Sharing : what the definition of JSA ?

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