Issue with Java Security Provider

While working on one enhancement. I encountered a weird problem. The program within WBIA framework failed in calling web service. It was throwing me a NullPointerException from Axis library as below:

at java.security.SecureRandom.nextBytes(SecureRandom.java:433)
at org.apache.axis.utils.SessionUtils.generateSessionId(SessionUtils.java:62)
at org.apache.axis.SOAPPart.<init>(SOAPPart.java:164)
at org.apache.axis.Message.setup(Message.java:377)
at org.apache.axis.Message.<init>(Message.java:246)
at org.apache.axis.client.Call.invoke(Call.java:2425)
at org.apache.axis.client.Call.invoke(Call.java:2366)
at org.apache.axis.client.Call.invoke(Call.java:1812)

I made the investigation as below:

1) I put a java.security.Security.getProviders() in my program to list all the security providers. I compared the results from successful call (standalone java program running at the same AIX server) and unsuccessful call (program extending from WBIA framework running at the same AIX server).

Here is the result:

//Unsuccessful call.
- IBMJSSE2
- IBMJGSSProvider
- IBMCertPath

//Successful call
- IBMJSSE2
- IBMJCE
- IBMJGSSProvider
- IBMCertPath
- IBMSASL

Obviously some security providers are missing hence caused the unsuccessful call. I double confirmed this by modifying my java.security file at local and tested the same program from my local. Yes the web service call actually failed due to the missing security provider. The missing security provider is actually com.ibm.crypto.provider.IBMJCE

Therefore, i did the below the solve this issue:

1) Set the Java home path to the JRE folder instead of the JDK folder itself.

2) I added the security provider at runtime.
java.security.Security.addProvider(new com.ibm.crypto.provider.IBMJCE());

Finally it worked. One question is, how come it somehow did not refer to the java.security file that i set everything correctly else i do not have to do the 2nd step as mentioned. I still need to find out this.

Load Test

Past few days i encountered one serious production issue, which the web service timeout before the backend process sent back the message to the SOAP response node in WMB flow. This was due to the high load in production that caused the delay in the backend process.

The whole process is: WMB flow extracts SOAP request message, turns it into a MQ Header message, puts the message to Java adaptor's request queue, then Java adaptor processes the content and puts a response message to the response queue, then WMB flow will read the message in the response queue and will turn it into a SOAP response.

In the progress of investigation, we decided to move one database query out from the java adaptor program to the WMB flow. The reason being is sometimes the db connection will just drop and the java adaptor program has to spend some time reinitiating the db connection. In fact according to the time recorded in the adaptor's log the process was still quite fast, it's even within miliseconds. Well we just gave it a try.

After making all the necessary changes we deployed the works to the testing environment. I then performed some load tests to the web service. The result was negative. The tps was around 3.5 but the average time taken was > 10 seconds and we had to achieve < 10 seconds! So still plenty of work to do :(

We performed a few cycles of investigation, trial and error & testing until we found the solution - increasing the WMB flow instance. This is a setting in the WMB Toolkit. So we increased the number of instances to 3. This time we managed to achieve an average time of 3 seconds! We were so happy and excited!

What about the cause? See below:

There were many messages piling at the response queue which is supposed to be read by the WMB flow. These messages were sent in by the Java Adaptor after it finished processing the data. Apparently these messages were not picked up by the WMB flow in time hence causing the timeout error. By increasing the WMB flow instance, concurrently there are 3 identical WMB flows reading the content of this queue, hence problem resolved!

I was really relieved!

Classloading in Websphere Administrative Console

I have this web service server application which has been running fine at a Websphere Process Server. One day, my application's log was writing to another application B's log. That is really weird. I checked and found out that this B was recently deployed to the server only. The cause for my application to write to B's log is due to B's log4j jar file was put in the server's common directory ! If we do not change the classloading policy, which is default to PARENT_FIRST, then Wepshere's classloader will load that common directory first only will load the jars in our application's WEB-INF/lib directory.

Hence i logged on to Websphere Administrative Console, went to my application's war file and changed the classloader policy to PARENT_LAST. By doing this Websphere will find and load the neccessary classes from your web module's WEB-INF/lib(web module classloader) first, also you must ensure that the jars you put under your application's WEB-INF/lib folder do not clash with the one at server's common directory, else you will get a java.lang.LinkageError exception due to classloader is trying to load duplicate class.

NullPointerException in SecureRandom.nextBytes

 

I was facing this issue where a web service client which had always been running fine suddenly stopped functioning properly due to an error NullPointerException in SecureRandom.nextBytes

AxisFault
faultCode: {http://schemas.xmlsoap.org/soap/envelope/}Server.userException
faultSubcode:
faultString: java.lang.NullPointerException
faultActor:
faultNode:
faultDetail:
{http://xml.apache.org/axis/}stackTrace:java.lang.NullPointerException
at java.security.SecureRandom.nextBytes(SecureRandom.java:406)
at org.apache.axis.utils.SessionUtils.generateSessionId(SessionUtils.java:62)

As you can see the exception was thrown when some class in Axis is calling the nextBytes function from SecureRandom Class. I spent quite some time in this and i think that is a bug for IBM version of JRE 1.4.2. If you want to know more, read here.
Therefore i changed the script which starts my web service client by using the java command from Java 5 instead of java 1.4.2 and finally it worked!

Busy with Web Services on WPS

For the past two weeks i had been very busy with building web services using java 1.4. Bad thing was i had to deploy them on Websphere Process Server 6.0,

I had no problem building the web services using Rational Software Architect(RSA). I tested my work by deploying to Websphere Application Server 6.1 runtime that comes together with the RSA. Everything was working fine.

However i started to have a lot of headaches while trying to deploy these web services by using Websphere Admin Consle to Websphere Process Server 6.0.2 which is running on a remote server. My web service application just could not start!

After trying out several solutions, in the end i migrated my source codes to Websphere Integration Developer 6.0(WID). I regenerated every web service related deployment configuration files and proxy classes by using WID.

This time my web service application started successfully! Well the next problem was it was unable to get database connection! It took me quite some time to figure out what's wrong with it and finally i realized that i had to get the JDBC connection from the WPS itself instead of creating my own OracleDataSource cache.

I created all JDBC connection that the web service applications needs by using the Websphere Admin Console. I also changed my code to get the JDBC connection via JNDI.
The method is simple. Just create a default initialContext, then within the context, get your JDBC connection by name like "JDBC/MyDB" will do.

Run java program at backend on Windows

Normally, if you want to start a Java program to run as back end process, just type the command follow by a '&'. However, how do you do the same on Windows?

Yesterday my colleague was facing this problem and i remembered i have gone through the same problem before in my previous company. After we went through the windows command list i found something, which is the 'start' command. Then i remembered i might have used this command before when i had faced the same problem last time.

So we tried the 'start' command and it was successful.

Why IT Project Fails!

I have come across an article talking about why IT project fails!

Take a look on it!

My experience told me that business users often do not want to spend much time with the developers during the development of a system. They do not realize that it is very very critical and useful to the final result of the system by spending time reviewing developers work to find out whether something is missing at the early phase of the project! Well i do agree that agile methodology approach is very very good provided the business users are willing to allocate resource to examine the system.