yuvaraj blog

noreply@blogger.com (Yuvaraj) — Wed, 17 Jul 2013 13:29:00 +0000

ORA-01000: maximum open cursors exceeded

Possible Fix :

1)Ensure Oracle 8.1.7 JDBC driver or a later version should be used

2)Java code can be checked for closure of ResultSet & Statement after the using this specific stored procedure

3) Increase the value of OPEN_CURSORS parameter in Oracle

Steps to fix:

1)Do static code check and all of the cursors/connections are closed properly in the java code

2) Ask DBA Team to check the value of OPEN_CURSORS parameter in Oracle and see whether the value is too less or not.

3)Further analysis is possible only if we are having details of all open cursors at the time of exception (DBA Team can provide the details of opened cursors)

noreply@blogger.com (Yuvaraj) — Wed, 17 Jul 2013 13:27:00 +0000

EPS file does not open correctly in photoshop-("Could not open or parse a DSC plate file because the file cannot be found"):

I have an issue from Customer saying that .eps file is not opened properly in photoshop application and throws the error "Could not open or parse a DSC plate file because the file cannot be found".

1)Downloaded open source viewer application such as InfraView and installed.The .eps file opened propely but in blurred form, so that I fgiured out some information is missing to reconstruct the file.
2)Tried to open in photoshop and got the error.I converted psd file to eps file which worked fine.At that time I came across options 'multiple file version/single file version' before saving the psd file to eps.
3)read more about EPS file format in internet and clarified about 'multiple file version/single file version'
4)Opened the error .eps file in Notepad++ and checked and found out .C,.M,.Y and .K files are missing and that was originally created as multiple file version.

Resolution:

EPS file was created as multiple file version and some of the files are missed out( Logo.C,Logo.M, Logo.Y,Logo.K ).
create single file version of eps file and upload the image to Application

noreply@blogger.com (Yuvaraj) — Wed, 17 Jul 2013 12:56:00 +0000

Unable to install the trial version of a product with IBM Installation Manager:

I downloaded trial version of rational application developer (RAD) from IBM website and tried to install the product. Normally all of the IBM products will be installed via IBM installation manager. The configuration file packed inside installation file (exe) will have information to obtain IBM product repository, in out case this is http link https://www-912.ibm.com/software/repositorymanager/action/getInitData

I clicked on the installation file which extracted the files to temporary location and started screens to install the installation manager and received popup with below error

CRIMC1085E: Resumable download failed for: https://www.ibm.com/software/repositorymanager/action/getInitData. CRIMC1083E: Failed to retrieve 'https://www.ibm.com/software/repositorymanager/action/getInitData'. CRIMC1084E: An exception is thrown while retrieving the file 'https://www.ibm.com/software/repositorymanager/action/getInitData' to 'C:\Users\ADMINI~1\AppData\Local\Temp\cicdip_Administrator\1374108030737\nf\cicURLLgetInitData7337285020417225312.tmp'. This issue can occur for different reasons. You might have an issue with your network connection. If you retrieve the file from a machine or network in your environment, the file system might be mounted incorrectly. On AIX, when you install from a file system that is mounted with the 'cio' option, the installation fails with the exception: A system call received a parameter that is not valid. Verify your network connection. If you retrieve the files from your environment, copy the source files to a different file system and install from that file system. java.net.ConnectException: Connection timed out: connect

I ignored the error and installed "IBM installation manager" and I restarted the installation manager and agian failed with same error, I ignored the error and the installation manager didn't have any repositories to install RAD. So I searched in Google and found IBM support page http://www-01.ibm.com/support/docview.wss?uid=swg21457139 which says "Turn Off firewall". But firewall is already disabled in my system.

My computer is connected to internet via proxy server and based on the error message I suspected that proxy server needs to be configured to obtain the repository information and I'm right.From the installation manager I clicked "Add Repositories" link and expanded "Internet" option and configured proxy server details.

How do we get repository information to install RAD ?

Accessed the link https://www.ibm.com/software/repositorymanager/action/getInitData obtained from error message which returns RAD repository data in XML tags. Specified the repository information in Installation manager which listed RAD 9.0 under installation packages.

Note:You need to provide credentials for proxy server and IBM site credentials when repository information is validated in installation manager.RAD repository location: https://www.ibm.com/software/repositorymanager/com.ibm.rational.application.developer.v9

noreply@blogger.com (Yuvaraj) — Mon, 12 Nov 2012 21:10:00 +0000

Websphere EJB Optimization: Convert pass by value calls to pass by reference without Local Interface

I've encountered a specific situation in the project where EJB calls should be optimized to reduce response time and memory footprint without modifying code.

Every J2EE programmer know about EJB local interfaces that enables EJB calls like local method calls as long as client and EJB resides in same physical machine. This option reduces overhead of data serialization and transfer between client and EJB layer and also reduces memory foot print since the data should be copied from one layer to another layer.

How do we enable the same feature for any existing project missing Local Interfaces ?

IBM websphere provides the following options to optimize EJB calls without adding local interfaces.

1) Set "Pass by reference" property in ORB service to true. Navigate to Application servers --> server_name --> Container services --> ORB service. Find the property "pass by reference" and set the value to TRUE.

2)Specify noLocalCopies in servant.jvm.options (-Dcom.ibm.CORBA.iiop.noLocalCopies=1).

Caution: We must ensure that the application is not negatively impacted by using pass-by-reference semantics. For example, if one bean passes another bean an object, expecting that the second bean can modify the object without affecting the first bean's object.

Unable to upload the TIF image of large dimensions 1920x1080 to Java Application

noreply@blogger.com (Yuvaraj) — Wed, 24 Oct 2012 15:46:00 +0000

I got an incident from customer saying that we are unable to upload TIF images to application and how ever they are able to upload when it was opened in Photoshop and saved.

I have raised this issue with third party and we were not having exact application logs to look into

Reason:

Application could not load this because it was missing the dimension information (width x height). This information is required in order for STEP to be able to load a TIFF image.

The dimension information is metadata on the file that is normally provided by whatever program the file was created in. Unfortunately, I cannot tell what program created this file, as it did not leave its name in the metadata either. Re-saving this image in any Photoshop application will supply the required metadata and then you should be able to import it into STEP. Just be aware that Photoshop will default to 72 dpi unless a different resolution is set.

Workaround:

Select all the images into Microsoft Picture Manager.
Click on Edit Pictures -- >Re-size and then select the required dimensions and press OK.
Click on File -- >Save All to save all the re-sized images

Please note that original images will be re-sized and make sure that back up original images in case if required

Java DNS Cache issues

noreply@blogger.com (Yuvaraj) — Wed, 24 Oct 2012 15:40:00 +0000

Java 1.5 DNS Cache issues:

Recently I encountered an issue with the application and things went pretty ugly. One of the database server is migrated from one hardware to another (copy DB to new HW) and DNS change was part of the implementation. The permissions on old database tables were revoked, but we are able to connect to that database.

Once all migration activities are completed I started testing our application (J2EE) connectivity to new database server (after couple of hours) I encountered permission issue on selecting database tables.

DBA's were telling that I'm still connecting to old servers and requested to point JDBC connection to new servers, but the fact is we have the new host name already in our JDBC string which is used in other part of the application.

Finally we figured it out the issue would have happened because of DNS cache and I found out that DNS queries to our new database server has TTL value of 3600 seconds, so Linux DNS cache is not an issue since I started testing couple of hours after DNS change.

use dig +ttlid <host-name> command in Linux to find out TTL value returned by DNS servers.

;; ANSWER SECTION:
google.com. 300 IN A 74.125.225.39
google.com. 300 IN A 74.125.225.34

The value of 300 is TTL for google.com and DNS entries for google.com will be flushed out from DNS cache after 300 seconds.

So where is the issue ?

Root Cause:

Java (1.4 & 1.5) has internal DNS cache whose entries never expires ( TTL =-1) which caused our application to connect to old servers.

Resolution:

Change the TTL value of Java DNS cache:

The SDK provides the following properties to control network address caching:
networkaddress.cache.ttl (default: -1)

You can use the following four properties to override the default behavior.

networkaddress.cache.ttl (default: -1)
Specified in the java.security file to indicate the caching policy for successful name lookups from the name service. The value is specified as an integer to indicate the number of seconds to cache the successful lookup. A value of -1 indicates "cache forever".
networkaddress.cache.negative.ttl (default: 10)
Specified in the java.security file to indicate the caching policy for unsuccessful name lookups from the name service. The value is specified as an integer to indicate the number of seconds to cache the failure for unsuccessful lookups. A value of 0 indicates "never cache". A value of -1 indicates "cache forever".
sun.net.inetaddr.ttl
This property is a sun private system property that corresponds to networkaddress.cache.ttl. It takes the same value and has the same meaning, but you can set it as a command-line option. However, the preferred way is to use the security property mentioned above.
sun.net.inetaddr.negative.ttl
This property is a sun private system property that corresponds to networkaddress.cache.negative.ttl. It takes the same value and has the same meaning, but you can set it as a command-line option. However, the preferred way is to use the security property mentioned above.

You can disable caching by adding -Dsun.net.inetaddr.ttl=0 on the command line starting the JVM. However, you cannot set the value of networkaddress.cache.ttl on the command line. You can set the required value in the java.security file, which is located in the %JRE%\lib\security directory.

Workarounds:

Upgrade to JDK 1.6 / JDK 1.7 which introduced changes to default DNS caching behavior. The TTL values are set to 30 seconds without a security manager.
JVM restart after DNS changes.

References:

http://www-01.ibm.com/support/docview.wss?uid=swg21207534
http://www-01.ibm.com/support/docview.wss?uid=swg21439843

noreply@blogger.com (Yuvaraj) — Wed, 17 Oct 2012 20:46:00 +0000

Websphere connection pool errors:ORA-02396: exceeded maximum idle time, please connect again

Today one of our application experienced Oracle time out errors “ORA-02396: exceeded maximum idle time, please connect again” when ever user submits long running operations and was able to re produce the same issue in my local environment with the help of debugger .

Oracle profile for the app user has idle time out of 45 minutes and when ever application took more than 45 minutes for processing the request and tries to update the results to DB, the application is throwing this error. Oracle discards idle connections after 45 minutes and for some reason websphere is not discarding this stale connections. Application is getting connection from Connection pool via JNDI lookup and closing out resources during method exits and not keeping the connection open.

The data source has the default values for connection pool properties.
Reap time: 180 seconds
Unused timeout: 1800 seconds
Aged timeout: 0 seconds
Global Transactions :No
EJB Transaction Attribute:Default (required) -CMT
Transaction started : Not in Web Layer/EJB Layer. DAO classes are opening connections.
Pattern: open/use/close pattern for DB connections.

I’ve changed “Aged timeout parameter” to 1200 seconds in my local environment which didn’t help. Not sure why Connection pool is keeping stale connections.

Finally I decided to do more research why stale connections are not discarded from Websphere connection pool even with appropriate settings.

The application specifies “required” transaction attribute for all container managed transactions and resource sharing scope is sharable for all local transactions (LTC).

According to websphere documentation when ever new JDBC connection is allocated under LTC (Local transaction containment) it is marked as having an affinity to the current LTC and when application closes the connection it is not returned to the pool until transaction ends and connection remains used by this transaction so connection pool mechanism can’t discard this connection even though it becomes stale connection.

Please refer http://www.ibm.com/developerworks/websphere/library/techarticles/0506_johnsen/0506_johnsen.html for more details.

I have verified this in my local websphere and when ever LTC has started the same logical connection is returned every time application tries to acquire db connection.

Here are some resolutions for this issue

1) Change the resource sharing scope of JDBC connections to “UnSharable” which creates more physical connection to database instead of sharing single physical connection using multiple logical connections and connection will be released to connection pool after application closes the connection.

2Add exception handler to specific part of the code and obtain new connection gracefully

3)Optimize application processing or long running queries

I did more research on the possible implementation of option (1) and it seems that option (1) is not feasible to implement with our application DB access pattern.

Resource sharing property can be specified either in web.xml or ejb-jar.xml along with resource reference (Datasource) and application code (servlet or EJB) should lookup the data source using this reference container will utilize sharable property (res-sharing-scope).How ever our app code is not using resource references to obtain database connection and instead obtain connections in DAO class.
Since the sharable property in CMConfigData (Connection Manager config Data) object in websphere object and it is not exposed outside (no setters) , the possibility of using IBM helper classes to set the sharable property in the opened database connection is blocked

We can implement Option 2 and 3 together and IBM also suggests handling StaleConnection exceptions in the code and more information is available at http://www.redbooks.ibm.com/redbooks/SG246688/axa.htm

noreply@blogger.com (Yuvaraj) — Wed, 17 Oct 2012 20:46:00 +0000

Debugging class loaders in WebSphere

We typically change the classloader from the default of PARENT_FIRST (i.e. get WebSphere to find/load the classes) to PARENT_LAST (i.e the application is responsible for finding/loading classes). However, when we did it for this application, we still got the same error: "java.lang.NoSuchMethodError". So, what we needed was some classloading debugging to find out what was going on...
Setting up debugging of classloaders in Websphere
If you have a dev instance of WebSphere 5.1/6 then the following process should work and allow you to get debugging going. (Note, sorry all you Firefox lovers, the WebSphere admin console needs IE to work for this as it will not allow you to set the right debugging modules.) To setup debugging, go to the Application Server settings (for MDF, this will be "server1")
1. Go to PROCESS DEFINITION > JVM and tick the "Verbose JNI" and "Verbose Classloading" and click on OK.
2. Click at the bottom, CUSTOM PROPERTIES and a new custom property called "ws.ext.debug" set to "true" and again click on OK
3. You have now set up the debugging flags for the bootstrap and system classloaders. You now need to do the same thing for the app servers three classloaders. From the Application server settings (again, "server" for MDF instances) click on LOGGING AND TRACING > DIAGNOSTIC TRACE and click on MODIFY button.
4. A window will pop up (this is the bit that does not work on Firefox) and you need to find (at the bottom) the "Websphere ClassLoader" and click and set to ENABLE ALL. When you click on OK, the text in the Trace Specfication will change to "WebSphere ClassLoader=all=enabled". Now change the log size (default is 20Mb, which is way to small) to around 200Mb. Click on OK. Now SAVE and Syncronise your changes and restart your app.
5. When you restart WAS, you will get a new log file called "trace.log" which will contain all the classloading debugging info, with the boostrap and system classloading going into the native_stdout/err logs.
You can see below the boostrap classloading extract - its a very big file as it outlines all classes WebSphere boots and loads.

...

|Opened /opt/websphere/asvr/java/jre/lib/jce.jar|

|Opened /opt/websphere/asvr/java/jre/lib/charsets.jar|

|Loaded java.lang.Object from /opt/websphere/asvr/java/jre/lib/rt.jar|

|Loaded java.io.Serializable from /opt/websphere/asvr/java/jre/lib/rt.jar|

...

The following sample shows the output in the trace.log (a very very big file, so you are going to need to use text manipulation tools like grep, sed or awk realistically)

...

6/21/07 12:44:47:994 BST]  1e88c7f CompoundClass > findClass name=org.w3c.dom.Node

this=com.ibm.ws.classloader.CompoundClassLoader@42d227

6/21/07 12:44:47:996 BST]  1e88c7f CompoundClass d class org.w3c.dom.Node found in

SinglePathClassProvider : com.ibm.ws.classloader.SinglePathClassProvider@ccd65d classpath =

/u01/websphere/asvr/installedApps/cell/app_war.ear/app.war/WEB-INF/lib/NCSO-6.jar

6/21/07 12:44:47:997 BST]  1e88c7f CompoundClass d loaded org.w3c.dom.Node from this=

6/21/07 12:44:47:998 BST]  1e88c7f CompoundClass d loaded org.w3c.dom.Node using classloader=

6/21/07 12:44:48:162 BST]  1e88c7f CompoundClass > loadClass name=org.w3c.dom.NodeList

this=com.ibm.ws.classloader.CompoundClassLoader@42d227

6/21/07 12:44:48:162 BST]  1e88c7f CompoundClass > findClass name=org.w3c.dom.NodeList

this=com.ibm.ws.classloader.CompoundClassLoader@42d227

...

http://www-1.ibm.com/support/docview.wss?rs=180&uid=swg21228700%3C/p%3E
http://websphere.sys-con.com/read/196105.htm%3C/p%3E
https://issues.apache.org/bugzilla/show_bug.cgi?id=38719#c2

noreply@blogger.com (Yuvaraj) — Wed, 17 Oct 2012 20:46:00 +0000

How to change the users passwords from J2EE Application ?

There are no generic J2EE API's to manipulate J2EE application user details.How ever each Application servers exposes MBeans to perform these operations through console or via scripting tools.
Eg: While creating the users from admin console, specifc mbeans will be called behind the scenes.

I wrote an example to reset the password for particular user using weblogic MBeans from Servlet.Eventhough this is not the exhaustive example which provides the basic steps for listing users/groups and modifying the user passwords


import java.io.IOException;
import java.io.PrintWriter;

import javax.naming.Context;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import weblogic.jndi.Environment;
import weblogic.management.MBeanHome;
import weblogic.management.security.RealmMBean;
import weblogic.management.security.authentication.AuthenticationProviderMBean;
import weblogic.management.security.authentication.GroupEditorMBean;
import weblogic.management.security.authentication.GroupMemberListerMBean;
import weblogic.management.security.authentication.MemberGroupListerMBean;
import weblogic.management.security.authentication.UserEditorMBean;
import weblogic.management.security.authentication.UserPasswordEditorMBean;
import weblogic.management.security.authentication.UserReaderMBean;
import weblogic.management.security.credentials.CredentialMapperMBean;
import weblogic.management.security.credentials.UserPasswordCredentialMapEditorMBean;
import weblogic.management.security.credentials.UserPasswordCredentialMapReaderMBean;
import weblogic.management.utils.InvalidParameterException;
import weblogic.management.utils.NotFoundException;

public class PasswordServlet extends HttpServlet
{

 protected transient MBeanHome home;

 
 /**
  * The doGet method of the servlet.

  *
  * This method is called when a form has its tag value method equals to get.
  *
  * @param request the request send by the client to the server
  * @param response the response send by the server to the client
  * @throws ServletException if an error occurred
  * @throws IOException if an error occurred
  */
 public void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException
 {

  doPost(request, response);
 }

 /**
  * The doPost method of the servlet.

  *
  * This method is called when a form has its tag value method equals to post.
  *
  * @param request the request send by the client to the server
  * @param response the response send by the server to the client
  * @throws ServletException if an error occurred
  * @throws IOException if an error occurred
  */
 public void doPost(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException
 {
  response.setContentType("text/html");
  findAdminHome();
  PrintWriter out = response.getWriter();
  RealmMBean[]realms= home.getActiveDomain().getSecurityConfiguration().findRealms();
  for(int n=0;n< authProviders.length; i++) {                       if (authProviders[i] instanceof UserEditorMBean) {                  out.println("UserEditorMBean: " + authProviders[i].wls_getDisplayName());              }               if (authProviders[i] instanceof GroupEditorMBean) {                  out.println("GroupEditorMBean: " + authProviders[i].wls_getDisplayName());              }               if (authProviders[i] instanceof MemberGroupListerMBean) {                  out.println("MemberGroupListerMBean: " + authProviders[i].wls_getDisplayName());                              }               if (authProviders[i] instanceof GroupMemberListerMBean) {                  out.println("GroupMemberListerMBean: " + authProviders[i].wls_getDisplayName());                                }               if (authProviders[i] instanceof UserReaderMBean) {               UserReaderMBean users=(UserReaderMBean)authProviders[i];                  try     {                   //String listUser=users.listUsers("USR*", 100);                         out.println("Users List: " +users.userExists("USR333"));      out.println("Users List: " +users.userExists("USR330"));     }     catch (InvalidParameterException e)     {      // TODO Auto-generated catch block      e.printStackTrace();     }                                }          }                for (int i = 0; i < credMappers.length; i++) {                            if (authProviders[i] instanceof UserPasswordCredentialMapReaderMBean) {               UserPasswordCredentialMapReaderMBean user=(UserPasswordCredentialMapReaderMBean)authProviders[i];                  out.println("UserPasswordCredentialMapReaderMBean: " + credMappers[i].wls_getDisplayName());              }               if (authProviders[i] instanceof UserPasswordCredentialMapEditorMBean) {                  out.println("UserPasswordCredentialMapEditorMBean: " + credMappers[i].wls_getDisplayName());              }               if (authProviders[i] instanceof UserPasswordEditorMBean) {               UserPasswordEditorMBean pwd=(UserPasswordEditorMBean)authProviders[i];               try     {      pwd.changeUserPassword("all", "allusers", "ALLUSERS");       out.println("Password Chnaged : " + credMappers[i].wls_getDisplayName());     }     catch (NotFoundException e)     {            e.printStackTrace();     }     catch (InvalidParameterException e)     {      e.printStackTrace();     }              }                                }          }   out.flush();   out.close();  }   private void findAdminHome()  {   Environment env = new Environment();   env.setProviderUrl("t3://localhost:7001");   env.setSecurityPrincipal("weblogic");   env.setSecurityCredentials("weblogic");    try   {    Context ctx = env.getInitialContext();    home = (MBeanHome) ctx.lookup(MBeanHome.ADMIN_JNDI_NAME);   }   catch (javax.naming.NamingException e)   {    e.printStackTrace();   }  }  }

noreply@blogger.com (Yuvaraj) — Wed, 17 Oct 2012 20:44:00 +0000

Connect to Websphere JDBC datasource from standalone Client:

We may hit a situation to connect to configured Websphere JDBC datasource from standalone java client and need appropriate drivers for target database we are connecting to.

There are no additional jars need to be downloaded from IBM website except database driver jar and we will be using IBM command(setupCmdLine.sh) to setup environment and connect to Oracle database.

Script to setup WAS environment and call Java Client:

# Use IBM script to initialize common WebSphere runtime settings

REPLACE_WAS_HOME=${WAS_HOME}

. $WAS_HOME/bin/setupCmdLine.sh

# Add oracle drivers to classpath

CLASSPATH="$WAS_CLASSPATH:/tmp/JDBC/ojdbc5.jar:."

# Specify JVM

JAVA="$JAVA_HOME/bin/java"

# Specify JVM command line options

JAVA_OPTS="-Djava.ext.dirs=$JAVA_HOME/jre/lib/ext:$WAS_EXT_DIRS:$WAS_HOME/plugins"

JAVA_OPTS="$JAVA_OPTS -cp $CLASSPATH"

$JAVA $JAVA_OPTS ConnectJDBC

Java Client:

import javax.naming.Context;

import javax.naming.InitialContext;

import javax.naming.NamingException;

import java.io.Serializable;

import java.sql.Connection;

import java.util.ArrayList;

import java.util.Hashtable;

import java.util.List;

import java.io.*;

public class ConnectJDBC {

public static void connect() {

final Hashtable env = new Hashtable();

env.put(Context.INITIAL_CONTEXT_FACTORY,"com.ibm.websphere.naming.WsnInitialContextFactory");

env.put(Context.PROVIDER_URL, "corbaloc:iiop::,::,::");

final Context jndiContext;

try {

jndiContext = new InitialContext(env);

} catch (NamingException e) {

System.err.println("Could not create JNDI API context: "+ e.toString());

System.exit(1);

return;

}

try {

javax.sql.DataSource ds = ((javax.sql.DataSource)jndiContext.lookup(""));

Connection conn =ds.getConnection(,);

String SQL = "{call . }";

} catch (Exception e) {

System.err.println("Could not perfrom JDBC Procedure Call: "+ e.toString());

System.exit(2);

}

public static void main(String[] args) {

connect();

}

Note: Please make sure the script #setupCmdLine.sh has appropriate permissions to avoid any failures. Note that standalone client will not be able use component-managed authentication for database and it's responsibility of client to provide authentication details during database connection..

Dependency Jars:

The standalone client need the following jars to connect to JDBC datasource configured in websphere when we are unable to use #setupCmdLine.sh script to setup the environment.

com.ibm.ws.runtime_6.1.0.jar

ojdbc14.jar

rsadbutils.jar

rsahelpers.jar

sibc.jndi.jar

sibc.jms.jar

sibc_install-o0902.06.jar

com.ibm.jaxws.thinclient_6.1.0.jar

Note: I performed all these tests using eclipse editor and Websphere 6.1 server.

noreply@blogger.com (Yuvaraj) — Wed, 17 Oct 2012 20:00:00 +0000

Post JMS messages to WebSphere queues from stand alone Client:

We may encounter a situation to send JMS messages to queues/topics configured in Websphere from standalone java program and unit/functional testing would be one good scenario for our case.

We need additional client libraries to lookup resources from JNDI and connect to websphere SIB and queues which can be downloaded from here.

Client Program:

import javax.jms.*;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.Hashtable;
import java.util.List;
import java.io.*;

public class PostJMSMessage {

public static void publish() {
final Hashtable env = new Hashtable();
env.put(Context.INITIAL_CONTEXT_FACTORY,"com.ibm.websphere.naming.WsnInitialContextFactory");
env.put(Context.PROVIDER_URL, "iiop://:");

final Context jndiContext;
try {
jndiContext = new InitialContext(env);
} catch (NamingException e) {
System.err.println("Could not create JNDI API context: "+ e.toString());
System.exit(1);
return;
}

try {
ConnectionFactory connectionFactory = (ConnectionFactory) jndiContext.lookup("");
Connection qConn = connectionFactory.createConnection();
Session qSession = qConn.createSession(false,Session.AUTO_ACKNOWLEDGE);
Queue q = (Queue) jndiContext.lookup("");

MessageProducer producer = qSession.createProducer(q);
ObjectMessage message = qSession.createObjectMessage();
message.setObject((Serializable) );
producer.send(message);

producer.close();
qSession.close();
qConn.close();
in.close();
} catch (Exception e) {
System.err.println("Could not perfrom JMS operation: "+ e.toString());
System.exit(2);
}
}

public static void main(String[] args) {
publish();
}
}

Jars required in classpath:

The following jars are required in classpath along with any application specific jars to compile and run the program

sibc.jms.jar

sibc.jndi.jar

sibc_install-o0902.06.jar

Compile & Run:

Navigate to the directory where the client program and jars are copied and find out IBM jdk path.

/opt/IBM/WebSphere/AppServer/java/bin/javac -cp :sibc.jms.jar:sibc.jndi.jar:. PostJMSMessage.java

/opt/IBM/WebSphere/AppServer/java/bin/java -cp :sibc.jms.jar:sibc.jndi.jar:. PostJMSMessage

noreply@blogger.com (Yuvaraj) — Mon, 25 Jul 2011 14:43:00 +0000

How to extract exception stack trace from javaEE application log file ?

I had the requirement to extract complete list of exception stack trace from java EE application log files for past 6 months and analyze the root cause for all exceptions.

I used the following sed commands to get the list which has all duplicate list of exceptions.

sed -ne '/ERROR/,/WebContainer :/p' *.log.2011* >/tmp/exception_list.txt
sed -i '/WARN/d' /tmp/exception_list.txt
sed -i '/INFO/d' /tmp/exception_list.txt
sed '/com.ibm.ws/d' -e '/org.apache/d' /tmp/exception_list.txt
sed -e '/com.ibm.ws/d' -e '/org.apache/d' /tmp/exception_list.txt

Remove duplicate exception block from the log.

1) Remove time/date information from log entry cut -f 2 -d']' exception_list.txt
2)Remove additional spaces if any sed 's/ ERROR/ERROR/' /tmp/exception_list.txt

uniq command will not work unless is sorted (sort), so use below command to remove duplicates with out changing line order

awk ' !x[$0]++' /tmp/exception_list.txt >/tmp/exception_list_final.txt

noreply@blogger.com (Yuvaraj) — Wed, 20 Jul 2011 19:40:00 +0000

How to delete duplicate MS communicator conversation copied to outlook History folder ?

Recently I faced below problem and couldn't find any solution/tools in internet. I decided to solve the problem myself.

I have enabled the option to save MS communicator conversation in outlook and the conversation will be saved to outlook at particular intervals. In case the chat session go beyond this interval, multiple copies of session will be saved with the information at the moment of interval timeout. i.e . The recent copy of the conversation includes all information from previous copy and all older copies can be deleted from outlook folder.

The tools to delete duplicate items didn't help here so I wrote VB script to handle this task myself. Here is the logic
1)Open Conversation History folder
2)Sort items by subject then Received in ascending order to group the items by subject and get the oldest item first among the subject
3) In first step mark the first item as pointer and named as X
4) In subsequent steps compared the subject of current item and previous pointer item (X) and if matches then verified body of item X contained in body of current item
5) If so then delete the item X
6) Outside the loop make current item as X and continue the loop

VB Script:


Set objOutlook = CreateObject("Outlook.Application")
Set objNamespace = objOutlook.GetNamespace("MAPI")
Set objFldr = objNamespace.Folders.Item("Mailbox - Ramasamy, Yuvaraj").Folders.Item("Conversation History")
Set colItems = objFldr.Items
colItems.Sort "[Subject][Received]", false
item_comp = Null
WScript.Echo colItems.count 
For Each objItem in colItems

If isNUll(item_comp ) then
 set item_comp = objItem
elseif (item_comp.subject = objItem.subject) then
 If left(objItem.body,len(item_comp.body)) = item_comp.body then
 item_comp.Delete
 end if
end if
set  item_comp = objItem
Next
WScript.Echo "all done"

noreply@blogger.com (Yuvaraj) — Fri, 22 Apr 2011 19:27:00 +0000

Change/delete locked symantec scheduled admin scan in Windows:

Most organizations should have installed some commercial Anti virus software in all IT assets (laptops/desktops etc...) and add READ ONLY configuration for daily quick scan and weekly scheduled full scan. IT administrators might have scheduled this on weekdays to ensure 100% completion of weekly scan and they don't want to abort any scan or postpone the scan schedule to number of days.

In my office laptop the scheduled weekly scan run on Wednesday's @11:30 AM and will take 5-6 hours to complete.Due to heavy disk scan and CPU contention I'm unable to use other resource hungry applications in my laptop (RAD/Firefox etc...).

Though we can't edit this settings from symantec UI, this can be exploited via registry editor.
Here are the steps to change SYMANTEC in Windowx XP:

1)Open registry editor (regedit)
2)Navigate to "HKEY_LOCAL_MACHINE\SOFTWARE\Symantec\Symantec Endpoint Protection\AV\LocalScans\{xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxx}\Schedule" and find out the key based on the name of the scheduled scan.
Note: Otherwise search entire registry for the schedule name (weekly scan wed@11:30) using Find(F4) option
3)Open the DWORD "DayOfWeek" and edit the value as appropriate (6 -for scan on Saturdays)

The schedule can be even deleted from the registry at your own risk which will completely remove the scheduled scan.

Under "LocalScans" you should see many nodes named "ClientScheduledScan_" or something similar. The "ClientScheduledScan_" is the node in the registry tree that registers my forced Administrator system scan with Symantec AntiVirus. Yours could be different, so you'll need to look around under LocalScans to find the correct one.

Here's a snapshot:

Disclaimer: Disabling admin scan on a PC by your employer is probably a violation of their IT-security policy and could get you into trouble.

noreply@blogger.com (Yuvaraj) — Thu, 14 Apr 2011 15:07:00 +0000

Running hadoop in Windows (Pseudo-Distributed Mode):

In previous post I have explained about starting hadoop as standalone service in windows.In this post I will explain how to start hadoop in pseudo distributed mode.In pseudo-distributed mode Hadoop daemon runs in a separate Java process in localhost

Configuration:
Add below mentioned configuration to start services required to mimic distribution mode

conf/core-site.xml:

<configuration>
<property>
<name>fs.default.name</name>
<value>hdfs://localhost:9000</value>
</property>
</configuration>

conf/hdfs-site.xml:

<configuration>
   <property>
       <name>dfs.replication</name>
       <value>1</value>
   </property>
</configuration>

conf/mapred-site.xml:

<configuration>
   <property>
       <name>mapred.job.tracker</name>
       <value>localhost:9001</value>
   </property>
</configuration>

We need to setup passphraseless ssh authentication to connect to localhost .Try $ ssh localhost and this should connect to your local machine with out prompting password/passphrase . If not please read below to setup openssh server/client and password less authentication

openssh client/server programs can be installed as part of cygwin installation by selecting "openssh" package during cygwin installation.
1)open cygwin console and run "ssh-host-config -y". This will generate configuration files required to start ssh server,setup local windows user account and creates windows service(sshd)
2)Now ssh service can be started either with cygwin command (cygrunsrv -S sshd) or standard windows command (net start sshd)

Note:Sometimes the service will not start and rebooting the system may help.

Run the following steps in cygwin console to setup public key authentication for ssh local connection

$ ssh-keygen -t dsa -P '' -f ~/.ssh/id_dsa
$ cat ~/.ssh/id_dsa.pub >> ~/.ssh/authorized_keys

Execution of hadoop in distribution mode:

Format a new distributed-filesystem:
$ bin/hadoop namenode -format

Start the hadoop daemons (this start name node and job tracker also)
$ bin/start-all.sh

The hadoop daemon log output is written to the ${HADOOP_LOG_DIR} directory (defaults to ${HADOOP_HOME}/logs).

Browse the web interface for the NameNode and the JobTracker; by default they are available at:

NameNode - http://localhost:50070/
JobTracker - http://localhost:50030

Stop the daemons with:
$ bin/stop-all.sh

Sounds simple.isn't it ??
How ever setting up public key authentication troubled me a lot due to issues with cygwin installation.I have deleted my previous installation files (without ssh server) and re installed cygwin along with open ssh client/server programs and followed the steps to start ssh server and public key authentication.

When I tried to connect to localhost via ssh i got password prompt which should not be the case.I deleted all the key pairs and followed the same steps to setup sshd service and public key authentication.But this it seems the correct keys were picked by ssh program and connection was closed by sshd and got below error message (Connection closed by ::1)

I decided to clean removal and installation of cygwin without any customization.

Follow below steps to remove cygwin in clean way:
1)Remove sshd configuration steps (cygrunsrv -E sshd and cygrunsrv -R sshd)
2)delete the folder (default -->c:\cygwin) and all its sub-folders
3)remove the Environment Variable CYGWIN and PATH variables if defined
4)Remove the following entries completely from registery (regedit)

HKEY_CURRENT_USER/Software/Cygnus Solutions
HKEY_CURRENT_USER/Software/cygwin
HKEY_LOCAL_MACHINE/Software/Cygnus Solutions
HKEY_LOCAL_MACHINE/Software_/cygwin

5)Remove local user/group sshd (compmgmt.msc)
6)Search for all public/private key files (id_rsa/id_dsa/id_dsa.pub/id_rsa.pub/authorized_keys) and delete them

Re-install cygwin in default path and make sure to select openssh packages as part of installtion and setup ssh server and password less authentication as indicated above.This time public key authentication worked for me and should work for you as well.

Now the important step is completed and happily executed command to start hadoop daemons.unfortunately I ended up with below error


localhost: Error: JAVA_HOME is not set.

Not sure why is this error occurred even after defining JAVA_HOME environment variable and this is not the case when I started hadoop in stand alone mode.I just followed apache documentation to fix this error.
edit the file conf/hadoop-env.sh to define at least JAVA_HOME to be the root of your Java
installation.

Finally I'm able to start hadoop in pseudo distribution mode in windows system and able to access Name node and job tracker via web url

Reference:
1) Apache Hadoop documentation
2) Setup Hadoop

noreply@blogger.com (Yuvaraj) — Wed, 13 Apr 2011 20:34:00 +0000

Running hadoop in windows machine:
Though windows supported as development platform by hadoop some tweaks are necessary to successfully start hadoop services.The following modes are supported by hadoop
Local (Standalone) Mode
Pseudo-Distributed Mode
Fully-Distributed Mode

Now we will see the steps to start hadoop in standalone mode in windows. I'm sure you will encounter one or more issues mentioned below when starting hadoop via cygwin

Required Software:
1)JavaTM 1.6.x, preferably from Sun
2)ssh must be installed and sshd must be running to use the Hadoop scripts that manage remote Hadoop daemons. (Cluster mode)
3)Cygwin
Download:
Download stable Hadoop distribution from Apache Download Mirrors.

Prepare to Start the Hadoop Cluster:
Unpack the downloaded Hadoop distribution.Define JAVA_HOME as environment variable or edit conf/hadoop-env.sh file
Try the following command:
$sh bin/hadoop
This should the usage documentation for the hadoop script without any start-up errors.

How ever you will get the error "C:\program command not found" if JRE is installed in default path (c:\program files\jre*")

How to fix this issue ?
Open the file hadoop-config.sh.Search for the text JAVA_PLATFORM=`CLASSPATH=${CLASSPATH} ${JAVA} and replace ${JAVA} with "${JAVA}" to handle space related issues in the file path while running hadoop via cygwin

Now this error will disappear and popup another error "java.lang.NoClassDefFoundError: org/apache/hadoop/util/PlatformName "

The class org.apache.hadoop.util.PlatformName exists in hadoop-common-*.jar.
The hadoop script automatically adds all necessary files CLASSPATH and it seems cygwin-style paths (/cygdrive/c/apps/hadoop-0.21.0) on classpath is not recognised properly when starting java runtime.

Note:set -x option can be used to debug the scripts

How to fix this issue now?

Open hadoop-config.sh file and add below line before using the CLASSPATH variable to define JAVA_PLATFORM (add after line JAVA_LIBRARY_PATH='')
CLASSPATH=`cygpath -p -w "$CLASSPATH"`

Now run $sh bin/hadoop which will display usage documentation like below

Usage: hadoop [--config confdir] COMMAND
where COMMAND is one of:
fs run a generic filesystem user client
version print the version
jar run a jar file
distcp copy file or directories recursively
archive -archiveName NAME -p * create a hadoop archive
classpath prints the class path needed to get the

noreply@blogger.com (Yuvaraj) — Fri, 01 Apr 2011 15:16:00 +0000

Remove deleted workspace names from "Switch Workspace" Menu in Eclipse based IDE

Sometime the deleted workspace names won't be removed from "switch workspace" list which may cause confusion to select the correct workspace.Here is the procedure to remove the entries from the list

Go to Eclipse/RAD installation directory (Eg:C:\Program Files\IBM\SDP) and find org.eclipse.ui.ide.prefs file under configuration\.settings.
Open the file org.eclipse.ui.ide.prefs in any favorite text editor and remove the unwanted values associated with key "RECENT_WORKSPACES".

Take care \n will be associated with every workspace name since this is maintained like bundle file.

noreply@blogger.com (Yuvaraj) — Mon, 22 Nov 2010 19:09:00 +0000

Problems encountered while deleting resources in RAD 6.1

Suddenly I started getting the "org.eclipse.core.internal.resources.ResourceException: Problems encountered while deleting resources." error when deploying EJB application to WSAD from RAD.The project is connected to Clearcase

I referred the following IBM url to understand about the problem which didn't help
http://www-01.ibm.com/support/docview.wss?uid=swg21369962

After bit of googling I found some meta data in workspace location is causing the problem.I opened .log file under the project workspace location and found more information about the error.

org.eclipse.core.internal.resources.ResourceException: Problems encountered while deleting resources.
at org.eclipse.core.internal.resources.Resource.delete(Unknown Source)
at org.eclipse.core.internal.resources.Resource.delete(Unknown Source)
at com.ibm.etools.ejbdeploy.properties.ResourceProperties.savePreferences(Unknown Source)
at com.ibm.etools.ejbdeploy.properties.ResourceProperties.setGenerationFolder(Unknown Source)
at com.ibm.etools.ejbdeploy.properties.ResourceProperties.getGenerationFolder(Unknown Source)
at com.ibm.etools.ejbdeploy.plugin.EJBDeployOperation.(Unknown Source)
at com.ibm.etools.ejbdeploy.plugin.EJBDeployBeansOperation.(Unknown Source)
at com.ibm.etools.ejbdeploy.EJBDeployer.getDeployOperation(Unknown Source)
at com.ibm.etools.ejbdeploy.EJBDeployer.visit(Unknown Source)
at com.ibm.etools.ejbdeploy.EJBDeployer.doExecute(Unknown Source)
at com.ibm.etools.ejbdeploy.EJBDeployer.execute(Unknown Source)
at org.eclipse.jst.j2ee.internal.deploy.J2EEDeployOperation.deploy(Unknown Source)
at org.eclipse.jst.j2ee.internal.deploy.J2EEDeployOperation.execute(Unknown Source)
at com.ibm.etools.server.task.ejbdeploy.EJBDeployableTask$EJBTaskOperations.execute(Unknown Source)
at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.performTasks(Unknown Source)
at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publish(Unknown Source)
at org.eclipse.wst.server.core.model.ServerBehaviourDelegate.publish(Unknown Source)
at org.eclipse.wst.server.core.internal.Server.publishImpl(Unknown Source)
at org.eclipse.wst.server.core.internal.Server$PublishJob.run(Unknown Source)
at org.eclipse.core.internal.jobs.Worker.run(Unknown Source)
Contains: UCM view "yuvaraj_ramasamy_dev_1.3.1" does not have a set activity

Resolution:

Rebased the current view and deployed the application again which resolved the issue

Related links:
http://www-01.ibm.com/support/docview.wss?uid=swg21316377

noreply@blogger.com (Yuvaraj) — Tue, 28 Oct 2008 15:05:00 +0000

How to implement Alpha Numeric Sequence (Increment AAAAZ to AAAB0)?

I faced the issue of generating the sequence of alphanumeric characters in pl/sql.PL/SQL supports the number sequences but not alpha numeric sequences.So decided to write one algorithm to perform the sequence generation


CREATE OR REPLACE FUNCTION batchseq_next(batchseq VARCHAR2) RETURN VARCHAR2 IS
str varchar2(5) :=batchseq;
inc char(1);
i number(2) :=5;
BEGIN
   IF(SUBSTR(str,   i,   1) = '9') THEN
     str := SUBSTR(str,   1,   i -1) || 'A';
     ELSIF(SUBSTR(str,   i,   1) != 'Z') THEN
       str := SUBSTR(str,   1,   i -1) || CHR((ASCII(SUBSTR(str,   i,   1)) + 1));
     else
     if(SUBSTR(str,   instr(str,'Z',1,1)-1,   1) ='9') then
     inc := 'A';
     else
     inc := CHR((ASCII(SUBSTR(str,   instr(str,'Z',1,1)-1,   1)) + 1));
     end if;
     str := SUBSTR(str,   1, instr(str,'Z',1,1)-2) ||inc|| translate (SUBSTR(str,   instr(str,'Z',1,1),   i),'Z','0');
     END IF;
RETURN str;
END batchseq_next;

noreply@blogger.com (Yuvaraj) — Mon, 10 Mar 2008 17:11:00 +0000

Some learnings in Hibernate:

1)Any number of associations can be joined using HQL Join.If we are using HQL Join Fetch and didn't specify second association in the HQL separate select statemnets will be fired for fetching the second association. (i.e) implicit association fetch depth is1
eg: Assume the relationships A-->B--> C .
The query "from A INNER JOIN FETCH B where ...." will eagerly fetch B not C. Separate select statements will be fired

2) While writing native SQL query try to use addEntity() to do value object conversion. We can fetch and convert the associations as well .
Eg:
Consider the one-many relation between parent and Child table

session.createSQLQuery("select pid,name,cid,c_pid,marks from PARENT p,CHILD c where p.pid=c.c_pid").addEntity("parent",Parent.class).addJoin("parent", "parent.childs").list(); -- won't eagerly fetch the associated children (Don't know the reason)

But the eager join fetching from child--->Parent is working fine .
session.createSQLQuery("select pid,name,cid,c_pid,marks from PARENT p,CHILD c where p.pid=c.c_pid").addEntity("child",Child.class).addJoin("child", "child.parent").list();

3)Sometimes it is not feasible to use HQL and implicit ValueObject coversion while using the aggregate functions.
I have examined two options to do implicit conversion instead of iterating over the result set.
I) Write native SQL and use addEntity() to perform the implicit conversion.This is not the good approach since the SQL syntax may change vendor to vendor
Ex:
session.createSQlQuery("select * from tbl where .... ").addEntity(entity.class)

II)Create the ValueObject with the required aggregate fields and then use Transformer to convert the ResultSet object to the DTO.
Ex:
HQL : select count(property),sum(property) ....
session.createQuery(buffer.toString()).
setResultTransformer( Transformers.aliasToBean(A.class)).list();

noreply@blogger.com (Yuvaraj) — Wed, 10 Jan 2007 09:38:00 +0000

PassPack and aSSL: "Francesco Sullo's day job is to work on PassPack an online password manager.

PassPack is based on the Host-Proof Hosting Ajax Pattern.

How it works

PassPack uses a double access technique: User ID and Pass give a user access to her Account, while the Packing Key is needed to access the actual passwords. The 'Pack' in PassPack comes from the bundle of locked up passwords inside the Account. PassPack checks the User ID and Pass at sign-in without exposing the passwords in the encrypted Pack.

Only the user can encrypt and decrypt the passwords in the browser with her Packing Key. The Packing Key never travels over the Internet. The encrypted Pack gets sent over SSL to the server for storage.

aSSL

Francesco works on aSSL in his spare time, and just released another new version with Javascript/ASP server-side component (PHP and others pending).

aSSL now works with the following process:

The browser calls the server to start the process.
The server returns its RSA modulus (e.g. the public key) and the public exponent (3 or 1000"

noreply@blogger.com (Yuvaraj) — Fri, 10 Nov 2006 04:38:00 +0000

Drawbacks of TimerTask: "Delayed and Periodic Tasks The Timer facility manages the execution of deferred ('run this task in 100 ms') and periodic ('run this task every 10 ms') tasks. However, Timer has some drawbacks, and ScheduledThreadPoolExecutor should be thought of as its replacement.[1] You can construct a ScheduledThreadPoolExecutor through its constructor or through the newScheduledThreadPool factory. [1]"