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

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 : 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.

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,
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               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.

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.

I am new to this and a bit rusty with Java, Oracle, Web Development, et al; and, I need a free trial run at this time, Can we do this?

I am new to this and a bit rusty with Java, Oracle, Web Development, et al; and, I need a free trial run at this time, Can we do this?

your itunes accoutn have nothing to d with your computer
you can go to any computer with internet access in the world and
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the itunes account is placed on apples itunes servers

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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 ?

Date formatting with java and axis

Hi,
My wsdl file has date field which uses xsd:dateTime data type. In my web service implementation java class I am passing value to this variable using Calendar.getInstance().
I am using Axis framework. When I check my soap output using TCP monitor I find that the date is of format eg: 2007-01-02T12:01:23.342Z.
The date output belongs to GMT and includes character Z. How do I get SOAP output in locale specific date time format. I used xsd:dateTime along with format parameter but no use.
Regards,
Shankar

The date is wrong because I ran the test using october
20th data and my data showed up.
The actual test is from 9/1 to 10/19.This still doesn't tell me what you tried, what you expected, or what you got. If you use the timestamps that you mentioned in your earlier post:
from: Wed Sep 01 00:00:00 CDT 2004
to: Wed Oct 20 00:00:00 CDT 2004
then you will get all timestamps from Sept 01 to Oct 19, inclusive. You won't get any on October 20 except for 00:00:00. Was that what you expected or was it not?
I'm still guessing here, but possibly the timestamps in your database aren't in the same timezone as CDT. If they are GMT timestamps then you'll be off by, what is it, three or five hours?

Is it possible to choose what data is and isn't shared with Lifelog?

Hi,
I was just wondering whether it is possible to change settings and customise what lifelog logs and what it doesn't?
I was planning to get a Sony Smartband, but I am not keen about sharing so much data... I would like to only use the Lifelog application for the fitness aspect if possible (I also don't see the point of stuff like logging which music I listened to...). Is it possible therefore to toggle what is shared with the application/what it logs? And if not are there any plans for this in a future release?
At the very least I would want to not share my photos with the application. If this is not possible I'm afraid I may have to look for an alternative fitness tracker to the Sony Smartband.
Thanks.

It's not possible, you can contact Sony directly
http://support.sonymobile.com/global-en/contactUs/
if you install and open LifeLog's settings
Personal data
Sony Mobile will collect detailed data about your location, physical activities, app usage, content consumed and your Sony Entertainment Network profile to provide this service. Sony Mobile will handle your data according to our Privacy Policy.
"I'd rather be hated for who I am, than loved for who I am not." Kurt Cobain (1967-1994)

Data management with Java & XQuery

As we can manipulate DB XML data with Java, when and why java programmers should consider XQuery instead ?

Thanks for the precision. So one advantage of Xquery is to use some kind of universal language allowing an exist programmer to come on board with DB XML or a DB XML programmer to do some stuff on an exist db (or any xml db supporting xquery)
To conclude of this subject in the particulary case of Oracle DB XML, are there some things you can do with Xquery that you can't in Java ? What can we tell in terms of performance for doing the same thing in Xquery and Java ?

[End of TNS data channel] with Java SDO API (JDBC thin 9.0.1.2.1)

Hello folks,
Environment:
Win2K, 1.2GHz Intel, 500MB RAM, Oracle 9i, Oracle JDBC Thin (9.0.1.2.1), JDK1.3
Our data in the DB is 2-D. It consists of SDO LineString geometries. We use SRID = 8307.
I run into this problem with Java SDO API. I got this exception: "Io exception: End of TNS data channel"
when I try to execute query that uses the SDO_RELATE function:
SELECT e.shape
FROM edge e
WHERE SDO_RELATE(e.shape,
mdsys.sdo_geometry( 2003, 8307, NULL,
mdsys.sdo_elem_info_array(1,1003,1),
mdsys.sdo_ordinate_array(-125.8,49.9,-125.6,49.9,-125.6,50.0,-125.8,50.0,-125.8,49.9) ),
'mask=ANYINTERACT querytype=WINDOW') = 'TRUE'
If I use SDO_FILTER instead of SDO_RELATE it works!
Here is how I execute the query in Java:
public int executeSpatialQuery(OracleConnection conn, String spatialQuery) throws Exception
int numberOfGeometries = 0;
conn.setDefaultRowPrefetch(1000);
Statement ps = conn.createStatement();
ResultSet rs = ps.executeQuery(spatialQuery);
while (rs.next()) {
numberOfGeometries++;
rs.close();
ps.close();
return numberOfGeometries;
Note: I was playing with the "conn.setDefaultRowPrefetch(n)" method hoping that there might be something to do with that but with no success.
Any help will be much appreciated. Thank you.
GKK

Hello folks,
Here is what I've done:
1. Created a "mini" Realtional model (modelB) which mimics exactly our existing "big" Realtional model (modelA). The tables, sequences, indices, etc. in modelB have been created in exactly the same fashion we'd created the corresponding entities in modelA. The only difference is that I preceeded the entities in our test modelB with "TEST_".
2. Populated the modelB with 1298 Lakes (3993 edges in total) in exatly the same fashion we use to populate our modelA - using a Data Loader based on Java SDO API.
3. Indexed the test modelB in exactly the same fashion as modelA.
4. Ran the query:
SELECT e.shape FROM test_edge e WHERE SDO_RELATE(e.shape,
mdsys.sdo_geometry(
2003,
8307,
NULL,
mdsys.sdo_elem_info_array(1,1003,1),
mdsys.sdo_ordinate_array(
-123.80833332065798,48.58352678668598,
-123.80833332065798,48.675352618459506,
-123.65050767229724,48.675352618459506,
-123.65050767229724,48.58352678668598,
-123.80833332065798,48.58352678668598
), 'mask=ANYINTERACT querytype=WINDOW'
) = 'TRUE'
in SQL*PLUS and it worked fine (retrieved a bunch of geometries)!
Ran the same query in the Daniel Geringer's OraTest utility and it worked this time and returned:
TIME : 1.222 seconds, TOTAL FETCH TIME 267 ROWS
Ran the query with our JCS Query Plug-In and it worked fine!
ANALYSIS
========
ModelA
======
- 59652 Lakes and 178764 edges
- it's properly indexed
- its SDO layers and geometries are valid
- when we count the number of related SDO geometries for this query we get:
SQL> SELECT count(e.shape) FROM edge e WHERE SDO_RELATE(e.shape,
2 mdsys.sdo_geometry(
3 2003,
4 8307,
5 NULL,
6 mdsys.sdo_elem_info_array(1,1003,1),
7 mdsys.sdo_ordinate_array(
8 -123.80833332065798,48.58352678668598,
9 -123.80833332065798,48.675352618459506,
10 -123.65050767229724,48.675352618459506,
11 -123.65050767229724,48.58352678668598,
12 -123.80833332065798,48.58352678668598
13 )
14 ), 'mask=ANYINTERACT querytype=WINDOW'
15 ) = 'TRUE';
COUNT(E.SHAPE)
267
- when we run the following query via the Java SDO API:
SELECT e.shape FROM edge e WHERE SDO_RELATE(e.shape,
mdsys.sdo_geometry(
2003,
8307,
NULL,
mdsys.sdo_elem_info_array(1,1003,1),
mdsys.sdo_ordinate_array(
-123.80833332065798,48.58352678668598,
-123.80833332065798,48.675352618459506,
-123.65050767229724,48.675352618459506,
-123.65050767229724,48.58352678668598,
-123.80833332065798,48.58352678668598
), 'mask=ANYINTERACT querytype=WINDOW'
) = 'TRUE'
it FAILS with: "TNS end of communaction channel"!
ModelB
======
- 1298 Lakes and 3993 edges
- it's properly indexed
- its SDO layers and geometries are valid
- when we count the number of related SDO geometries for this query we get:
SQL> SELECT count(e.shape) FROM test_edge e WHERE SDO_RELATE(e.shape,
2 mdsys.sdo_geometry(
3 2003,
4 8307,
5 NULL,
6 mdsys.sdo_elem_info_array(1,1003,1),
7 mdsys.sdo_ordinate_array(
8 -123.80833332065798,48.58352678668598,
9 -123.80833332065798,48.675352618459506,
10 -123.65050767229724,48.675352618459506,
11 -123.65050767229724,48.58352678668598,
12 -123.80833332065798,48.58352678668598
13 )
14 ), 'mask=ANYINTERACT querytype=WINDOW'
15 ) = 'TRUE';
COUNT(E.SHAPE)
267
- when we run the following query via the Java SDO API:
SELECT e.shape FROM test_edge e WHERE SDO_RELATE(e.shape,
mdsys.sdo_geometry(
2003,
8307,
NULL,
mdsys.sdo_elem_info_array(1,1003,1),
mdsys.sdo_ordinate_array(
-123.80833332065798,48.58352678668598,
-123.80833332065798,48.675352618459506,
-123.65050767229724,48.675352618459506,
-123.65050767229724,48.58352678668598,
-123.80833332065798,48.58352678668598
), 'mask=ANYINTERACT querytype=WINDOW'
) = 'TRUE'
it SUCCESSFULLY returns the related geometries!
So, what can we make of all this? We know that there exists a model for which the SDO_RELATE works via the Java SDO API. This model is a subset (w.r.t. the data set) of our original model in which we detected the "TNS end of communication channel problem". The environment we used for these tests is exactly the same: JDBC Thin driver (version 9.0.1.0.0), Oracle9i Enterprise Edition (Release 9.0.1.2.1 - Production).
One can think that the problem lies in the Oracle Object-Realational or Oracle Spatial but the fact that we can successfully execute the same SDO_RELATE queries in SQL*PLUS rejects this possibility. Perhaps it depends on the amount of data passed to the JDBC driver and the fashion in which it handles it! In our test above we had RELATED 267 geometries. We know that there exist SDO_RELATE queries that run successfully with modelA, but those are queries which ONLY retrieve an EMPTY set of RELATED geometries. In other words we don't get the "TNS end of communication channel" because NO data gets fetched from the server to the client! As soon as we find a SDO_RELATE query which retrieves (RELATES) at least 1 geometry that runs successfully in SQL*PLUS and run it via the Java SDO API - it FAILS! This means that no matter what volume of data is fetched from the server-JDBCThin-SDOAPI-client as long as there is ANY data, the query FAILS in modelA.
Perhaps something internally in the Oracle 9i Server happens that prevent the data being fetch to the JDBCThin for that particular modelA. But what that might be?
Very peculiar problem!
Regards,
Georgi

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Hello,
I am creating a demo Enterprise Mobile App, for cross platform and I want to use the Data Vault.
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allTests.add("test1");
allTests.add("test2");
allTests.add("test3");
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inside AppModuleImp.java
I tested this implementation through AppModule Oracle ADF Model Tester and it returns test1,test2,test3. So this is OK. Now I publisher function through Client Interfaces, and I can see it know in DataControl.
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The solution is
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allTests.add("test1");
allTests.add("test2");
allTests.add("test3");
return allTests;
Problem was in generic List

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I have some Service Runinig on My Windows machine like Tomcat Server,i want to update some file in Tomcat server through java program ,it works only when my tomcat stops ,I want to write peice of Code so that i can stop service with my prog and start after updating my files

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