Googles Android

Hi Guys,

Googles Android is an operating system for mobile devices ,and even it act as middleware.They have given SDK for different OS.So It has its own JVM.U can download the SDK and u can develop the applications using API given by google.Now Emerging market becomes for mobile OS .Now already Mobile OS war is going on with Apple's Iphone and googles Android.

But one wonderful feature Given by google was its given entirely open source code.
u can develop the applications and distribute to different vendors,so that economically u can also survey as u have Zeal.

Here is the link check it

http://code.google.com/android/what-is-android.html

Transactions In EJB,Spring->Part1

Transactions in Spring and EJB Context.

I will go to straight point to how Transactions useful ,instead of explaining all ACID Properties .In this first part we will discuss about types of transactions.

There are 3 types of transaction u see in the java world.

1) Local Transactions
2) Programatic Transactions.
3) Declarative Transactions.

1) Local Transactions :

In Local Transactions ,u no need to worry about the transactions ,underlying managers take care ,for example if u take JMS related transactions there is QueueConnectionFactory which is the resource manager take care, if u take jdbc related things it will take care of default commit, u no need to worry about the things.

But say

Connection con=datsource.getConnection();
Statement st=con.createStatement();
String sql=”some statement”;
String sql1=”some statement”;

Try {


St.executeUpdate(sql);
St.executeUpdate(sql1);

Con.commit();
}catch(Exception e)
{
Con.rollback();

}

Here Defaulty transaction Manager will commit 2 things ,as we didn’t set autoCommit false.Say for example. First executeUpdate executes fine then any problem occurs,the rollback will happen to only upto 2nd statement.First execute Update statement still commited. So inorder to maintain Local Transactions , we will use

Con.setAutoCommit(false);

So Even one execute Statement fails automatically we can roll back all the statements.


2) Programatic Transactions :

Here in this Developer manages the transactions not like local transactions giving control to resource mangers to handle the transaction. Here the Comes for JTA(Java Transaction API).There one interface named UserTransaction Comes to picture.

Say in EJB. U will get the SessionContext or messsageDrivenContext what ever

UserTransaction ut= sessionContext.getUserTransaction;
ut.begin();
//write code
Ut.commit();

Where ever u want which individual statements want to commit or roll back u can decide and write the code.


3)Container Managed Transactions:

Here The developer don’t want to write code as begin,commit ,rollback Every thing container will take care ,just developer can say which method to do transaction and behaviour of transactions.

In EJB we can declare it in ejb-jar.xml file.

There are 6 attributes like never,Mnadatorey,Required etc given by EJB Container.Ofcourse In Spring Propagation_nested attribute extra added for chaining.

We will discuss these transactions in depth and even how it will help developers where to use each type of transactions and drawbacks of all these.Here for time being iam not discussing about spring Transactions.In next session we will discuss spring related transactions even too. Have a good Day !!!

Frameworks

Hi ,

A New Framework came called "Play Framework" came for exisistane for java.
It has features

1) Framework automatically load and compile when u change the source files.
2)Vrey Good error reports.IF Exception occurs it shows directly into source code where error occurs.
3)simple MVC Support based,hibenate u can simply develop a web application
4)Containig A fast http server
5) Having some plugins for even spring ...

chcek it out if u want to try www.playframework.org

Books for SCJP,SunwebServices certfication

hi ,

The good Books to follow for SCJP are

1) SCJP--> By Kathie Seria
2) SCJP --->Khalid Moghal

For Sun webservices Certification

1) J2EE Webservices --> By RMH

finding jars

Hi ,
If you want to get jars there is already one site http://www.jarfinder.com . where u can serach for required jars based on class name or jar name.Just check it out.