Saturday, 14 December 2013

Types of Mobile Applications: Difference between Native, Hybrid and Web applications

There are many contradictory views on the various types of mobile applications that can be developed for mobile devices

Mainly most mobile applications can be-

1) Native Mobile Applications :
Completely coded using the sdk of the various platforms (like Android and iOS).
The language is used to implement both UI and functionality.
Native applications can use device functionality like camera,contacts et cetera.


2)Hybrid Mobile Applications:
Such applications use a skeleton native application and load web content in it
This web content may be static(where the served html,js,css etc are packaged with the application and reside on a users device) or dynamic (where the content is served from a server)
You can use the various HTML5 technologies and come up with an amazing user interface.
Hybrid applications can use device functionality like camera , contacts et cetera,thanks to the skeleton native application.

3)Mobile Web Application::
This is your traditional  web application loaded on a device browser (Eg : WebKit,Chrome,Firfox on Android)
This may be (or may not be) different from the application that loads in your desktop browser.
For example-m.facebook.com is the mobile web application of facebook.com
Application developers can customize their websites to load content more efficiently ,given the limited resources of a mobile device.
Mobile web applications cannot use device functionality


Check out this really cool video by Intel differentiating between how content is served in a mobile web application and in a hybrid mobile application.

Monday, 11 November 2013

Debugging application startup with plugins in Websphere Application Server

This post mainly addresses the errors observed during installing a application in Websphere Application Server . Most of the stuff I shall write about are generic to WAS 7 ,WAS 8 and WAS 8.5

1) So what happens when you install a new application through the WAS Admin console , and post successful installation it does not start ???

Observe the application startup logs in  your application server folder in profile
Eg : C:\IBM\WebSphere\AppServer\profiles\AppSrv01\logs\server1
or C:\IBM\WebSphere\AppServer\profiles\AppSrv01\logs\webserver1
Go through the logs and you should get idea of whats wrong.

2) If Step 1 fails , and the logs show only IBM related errors, then it might be a good idea to look for and install any applicable fixpaks. These fixpaks are cumulative so the latest should suffice

Eg: I was trying to install an application in WAS 8.5 and though the installation was successful , the applciation would not start .  The logs at C:\IBM\WebSphere\AppServer\profiles\AppSrv01\logs\ffdc
said  :
[11/11/13 9:40:36:513 IST]     FFDC Exception:com.ibm.ws.exception.RuntimeError SourceId:com.ibm.ws.runtime.component.CompositionUnitMgrImpl ProbeId:679 Reporter:com.ibm.ws.runtime.component.CompositionUnitMgrImpl@e341fce8
com.ibm.ws.exception.RuntimeError: java.lang.RuntimeException: java.lang.ArrayIndexOutOfBoundsException
at com.ibm.ws.runtime.component.ApplicationMgrImpl.startApplication(ApplicationMgrImpl.java:792)
..
..
..
Caused by: java.lang.ArrayIndexOutOfBoundsException
at org.objectweb.asm.ClassReader.readClass(Unknown Source)
at org.objectweb.asm.ClassReader.accept(Unknown Source)
at org.objectweb.asm.ClassReader.accept(Unknown Source)

Appeared to be an application issue,but after a lot of browsing realised that the fix was in one of the fixpaks
So stay on the latest fixpak if possible

Now what happens when you application has started successfully

1)Try to access your application through the application server port
Eg: http://localhost:9080/<context-root>/<web-page>

If this works well for you , that means the setup is correct
Otherwise,ensure that the URL you are accessing is correct, and simple html,jsp files etc are accessible

2) If you'r able to access your URL through the application server,but you are getting a 404 error on trying to access it through the web server ,follow the below mentioned steps :
-Make sure your http.conf has the following entries :
LoadModule was_ap22_module "C:\IBM\WebSphere\Plugins\bin\32bits\mod_was_ap22_http.dll"
WebSpherePluginConfig "C:\IBM\WebSphere\Plugins\config\webserver1\plugin-cfg.xml"

-Check your webserver logs  for errors
Eg : Ensure the follwoing text appears
[Mon Nov 11 12:57:52 2013] [notice] PLUGIN: mod_was_ap22_http: apache_log_header: WebSphere Plugins loaded.
[Mon Nov 11 12:57:52 2013] [notice] PLUGIN: mod_was_ap22_http: apache_log_header: --------------------Plugin Information-----------------------
[Mon Nov 11 12:57:52 2013] [notice] PLUGIN: mod_was_ap22_http: apache_log_header: Bld version: 8.5.0
[Mon Nov 11 12:57:52 2013] [notice] PLUGIN: mod_was_ap22_http: apache_log_header: Bld date: Apr 24 2012, 15:12:31
[Mon Nov 11 12:57:52 2013] [notice] PLUGIN: mod_was_ap22_http: apache_log_header: Webserver: IBM_HTTP_Server
[Mon Nov 11 12:57:52 2013] [notice] PLUGIN: mod_was_ap22_http: apache_log_header: --------------------------------------------------------------

My log had additional errors: 
File does not exist: C:/IBM/HTTPServer/htdocs/<application context-root>
Since plugins were configured ,this meant that the plugin-cfg.xml file was incomplete
Read on to know more ...

-plugin-cfg.xml
When any application has to be rerouted to the application server to the web server,plugins need to be generated specifically for that application . One plugin-cfg.xml file is updated(Operation "Generate plugins") and propagation involves pasting this file in the various app server,web server and dmgr locations (Operation "Propogate Plug In") . 

Sample locations :

C:\IBM\WebSphere\Plugins\config\webserver1\plugin-cfg.xml

C:\IBM\WebSphere\AppServer\profiles\Dmgr01\config\cells\CFWIN2012X64-4Cell01\nodes\CFWIN2012X64-4Node01\servers\webserver1\plugin-cfg.xml

C:\IBM\WebSphere\AppServer\profiles\AppSrv01\config\cells\CFWIN2012X64-4Cell01\nodes\CFWIN2012X64-4Node01\servers\webserver1\plugin-cfg.xml 

If any time a plugin-cfg.xml is created in the Dmgr01 file path ( as shown in sample location 2) , any changes made to the plugin-cfg.xml are not reflected to it.Hence it will always remain out of sync with the other plugin-cfg.xml files

 The trick is to make sure all the plugin-cfg.xml files are in sync,bear the same timestamp and content.just search plugin-cfg.xml files in your IBM roots,copy paste and restart web server.

This will also resolve the incomplete plugin-cfg.xml issue mentioned above


.

Wednesday, 22 May 2013

Friday, 19 April 2013

Spring!

Spring! by Viny N
Spring!, a photo by Viny N on Flickr.

In wait of spring and rain

Monday, 15 April 2013

Monday, 1 April 2013

Increasing deployment timeout for jboss7.1.0

Sometimes EAR deployment fails as it needs more time to deply than the timeout specified in your JBOSS7.1 config files

In such cases we get errors like :


23:33:19,789 INFO  [org.jboss.as.server] (DeploymentScanner-threads - 2) JBAS015870: Deploy of deployment "abc.ear" was rolled back with failure message Operation cancelled
23:33:19,795 ERROR [org.jboss.as.server.deployment.scanner] (DeploymentScanner-threads - 1) JBAS015052: Did not receive a response to the deployment operation within the allowed timeout period [60 seconds]. Check the server configuration file and the server logs to find more about the status of the deployment.

Searching the standalone.xml file for timeout might not help if its a fresh install of jboss 7.1 as these values are default.
You have to explicitly set it in the standalone.xml file

Steps are as follows:

1)Stop jboss server
2)Goto jboss-as-7.1.0.Final/standalone/configuration
3)Edit standalone.xml file
4)Search for he following block of code

 <subsystem xmlns="urn:jboss:domain:deployment-scanner:1.1">
            <deployment-scanner path="deployments" relative-to="jboss.server.base.dir" scan-interval="5000"/>
        </subsystem>

In this case deployment timeout defaults to 60 seconds
5)Add deployment-timeout value

 <subsystem xmlns="urn:jboss:domain:deployment-scanner:1.1">
            <deployment-scanner path="deployments" relative-to="jboss.server.base.dir" scan-interval="5000" deployment-timeout="300"/>
        </subsystem>

Now the deployment timeout value has been set to 300 secands.You can configure it as per your need
6)Start jboss server and deploy your app.




Tuesday, 5 February 2013

ColdFusion IceBreaker #8 : ColdFusion 32 bit or 64 bit ???

So what happens when you take over an existing ColdFusion installation and want to update it ?
Or something doesn't work and you want to verify if its "supposed" to work for a particular bit version???

Its a bit typical to check whether ColdFusion was installed in its 32bit or 64 bit flavor,particularly if you were not the one who installed it

Here are a few ways to detect the current bit version of your installed ColdFusion server

1)Use your install logs

Open the install log (Adobe_ColdFusion_X_xxxxx(optional for 9)_InstallLog.log.
It will contain the following information:
-java.version :  This is the version of the Java used in the installer.Might not necessarily match your system's java version
-java.vm.name : Observe this carefully .If its a 64bit install ,this value will mention 64 Eg: Java HotSpot(TM) 64-Bit Server VM' .If its a 32 bit install there wont be any such mention Eg: Java HotSpot(TM) Server VM
Instead of "Server" it might say "Client' depending on installation,but that is irrelevant for judging whether its a 32bit or a 64 bit install
-os.arch : This explicitly states x86 for 32 bit install and x64 for 64 bit install

2)Use java -version

Goto <ColdFusion-Home>/runtimr/jre/bin
Give java.exe -version
You should be able to see java version,runtime environment and the java vm name

N.B. The Java information in Administrator->System information reflects the java that CF is using as opposedto the java that the installer used,so don't count on it

Tuesday, 22 January 2013

Adding extra packages to Android SDK

Recently I wanted to download some additional packages to my existing Android SDK.

The simplest way to go about anything is seemingly the UI way.

So I went ahead and launched my Android SDK from the Start Menu.,and as expected it displayed the sdk contents.But to my absolute amazement ,even thought the updates options was checked the Packages View would not show me any updates to the folders.
All it would show me was that updates were available for "Android SDK Tools" and "Android SDK Platform-tools".



Since I had no use for an update I happily ignored those two and focussed on the Extras folder which is where the said packages were supposed to reside.
No matter how many restarts I made to the SDK Manager (including launching it from eclipse,starting it from Start menu with administrator permissions)

Finally I decided to do the minimal and updated the suggested updates to  "Android SDK Tools" and "Android SDK Platform-tools" and restarted the SDK  Manager

And to my utter surprise .....

The Packages View goes ahead and shows all that is available for download in all the expected folders: Tools,Various Android Versions and the Extras.
now it was easy to download whatever I required .



Moral of the Story : Need an extra package? update exisiting packages and restart SDK Manager (run as administrator)

Monday, 21 January 2013

A day out in the sea...

A day out in the sea... by Viny N
A day out in the sea..., a photo by Viny N on Flickr.

A beautiful girl enjoying a day at the seas..

Sunday, 13 January 2013

Wednesday, 9 January 2013

Lushness!!!

Lushness!!! by Viny N
Lushness!!!, a photo by Viny N on Flickr.

Some flowers....and lots of sunshine :)