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Saturday, March 12, 2011
What is J2ME Apps Dev
J2ME or also know as Java ME is a platform that is specifically designed for application development to run on mobile phones, PDAs and other embedded systems. J2ME development features an adaptable user interface, which integrates with network protocols and extends support for mobile application development.
The mobile applications that are developed on J2ME can be also migrated across various different mobile devices. J2ME application developers create a variety of different mobile applications based on the customized requirements of the clients. They are experience in creating diverse mobile solutions and hence most clients prefer to outsource their mobile business applications to India.
J2ME Architecture and configuration
J2ME comprises of configurations and profiles that allow a developer to customize it for the Java Runtime Environment (JRE). The configuration defines the JVM used and the profile adds domain-specific classes to define the application.
Configurations: The configuration uses a set of core classes and a specific JVM to define the basic run-time environment. The configurations are of two types where one is called CLDC for handled devices and the second one is CDC for plug-in devices. CLDC is has been developed for 16-bit or 32-bit small computing devices that have limited memory. CDC requires a 32-bit architecture and has at least 2 MB of memory and implements a functional JVM.
Profiles: A profile comprises of classes that allow J2ME application developers to execute features that are typically available on a group of small computing devices. The profiles used with CLDC are mobile information device profile (MIDP) and PDA profile (PDAP). The profiles used with CDC include Foundation Profile, Game Profile, Personal Profile, Personal Basis Profile and RMI Profile.
J2ME Architecture
The J2ME architecture consists of five layers and they are as follows:
The mobile applications that are developed on J2ME can be also migrated across various different mobile devices. J2ME application developers create a variety of different mobile applications based on the customized requirements of the clients. They are experience in creating diverse mobile solutions and hence most clients prefer to outsource their mobile business applications to India.
J2ME Architecture and configuration
J2ME comprises of configurations and profiles that allow a developer to customize it for the Java Runtime Environment (JRE). The configuration defines the JVM used and the profile adds domain-specific classes to define the application.
Configurations: The configuration uses a set of core classes and a specific JVM to define the basic run-time environment. The configurations are of two types where one is called CLDC for handled devices and the second one is CDC for plug-in devices. CLDC is has been developed for 16-bit or 32-bit small computing devices that have limited memory. CDC requires a 32-bit architecture and has at least 2 MB of memory and implements a functional JVM.
Profiles: A profile comprises of classes that allow J2ME application developers to execute features that are typically available on a group of small computing devices. The profiles used with CLDC are mobile information device profile (MIDP) and PDA profile (PDAP). The profiles used with CDC include Foundation Profile, Game Profile, Personal Profile, Personal Basis Profile and RMI Profile.
J2ME Architecture
The J2ME architecture consists of five layers and they are as follows:
- MIDP: This is the topmost layer and consists of Java APIs. J2ME application developers use these APIs to create network connections, storage, and user interface. It also provides access to CLDC libraries and MIDP libraries.
- J2ME API's: This is the profile that comprises of a minimum set of application programming interfaces required for the small computing devices.
- Configurations: This is responsible to manage the interactions between the JVM and the profile.
- JVM
- Operating System: This is the bottom layer.
Friday, March 11, 2011
What is java used for
Java is a highly popular programming language and computer platform originally developed in 1995 by Sun Microsystems when the existing software, called OAK, was renamed. According to the Java website, 850million worldwide use Java and the software is claimed to be integral to a wide variety of computing functions including business intranet applications and other e-business software.
Java runs on something called the Java Runtime Environment (JRE) which consists of the Java Virtual Machine (JVM), Java platform core classes and supporting Java libraries. The JRE enables you to run the software in your web browser.
Originally Java was intended for the television industry but it became apparent that the software was too advanced for the cable technology of the time. Java incorporates a function called 'Write Once, Run Anywhere' which means that the code can be written on a PC but also used on a wide variety of other devices that use JVM such as Java-enabled cell phones, routers and mainframes. It does this by using something called Java Bytecode which can be interpreted by the JVM. The intention behind this is to eliminate the situation whereby a software developer has to rewrite the programming language to suit a different machine. Unfortunately, this hasn't worked as well as it was originally hoped since there can be many Java implementations alongside other operating systems such as Windows, Mac OS and Linux. This has led to some developers re-christening Java as 'Write once, debug everywhere'.
In its early forms Java had a reputation for being rather slow in comparison to programs written in the usual C. However in 1998, Java 1.1 was released with Just-in-time compilation (JIT) also known as dynamic translation, the function of which is to speed up the execution of the bytecode. Java also uses an automatic garbage collector in order to manage memory automatically. This can activate at any time but is most likely to activate when a machine is idle.
In 2006 Sun released Java as open-source software and versions of it can now be freely downloaded. The website claims that it's an essential piece of software on the basis that many websites and applications, including online gaming, won't run without it. I certainly remember the odd occasion when a piece of software has failed on me because I didn't have Java installed and so I have now installed a free version on my PC just before writing this. In addition, for those who want to use Java for programming, I would mention there are a load of tutorials available on the internet from the business software website Oracle. If you want to learn programming using Java it might therefore be worth your while downloading those as well.
Java runs on something called the Java Runtime Environment (JRE) which consists of the Java Virtual Machine (JVM), Java platform core classes and supporting Java libraries. The JRE enables you to run the software in your web browser.
Originally Java was intended for the television industry but it became apparent that the software was too advanced for the cable technology of the time. Java incorporates a function called 'Write Once, Run Anywhere' which means that the code can be written on a PC but also used on a wide variety of other devices that use JVM such as Java-enabled cell phones, routers and mainframes. It does this by using something called Java Bytecode which can be interpreted by the JVM. The intention behind this is to eliminate the situation whereby a software developer has to rewrite the programming language to suit a different machine. Unfortunately, this hasn't worked as well as it was originally hoped since there can be many Java implementations alongside other operating systems such as Windows, Mac OS and Linux. This has led to some developers re-christening Java as 'Write once, debug everywhere'.
In its early forms Java had a reputation for being rather slow in comparison to programs written in the usual C. However in 1998, Java 1.1 was released with Just-in-time compilation (JIT) also known as dynamic translation, the function of which is to speed up the execution of the bytecode. Java also uses an automatic garbage collector in order to manage memory automatically. This can activate at any time but is most likely to activate when a machine is idle.
In 2006 Sun released Java as open-source software and versions of it can now be freely downloaded. The website claims that it's an essential piece of software on the basis that many websites and applications, including online gaming, won't run without it. I certainly remember the odd occasion when a piece of software has failed on me because I didn't have Java installed and so I have now installed a free version on my PC just before writing this. In addition, for those who want to use Java for programming, I would mention there are a load of tutorials available on the internet from the business software website Oracle. If you want to learn programming using Java it might therefore be worth your while downloading those as well.
What is foreign keys in relational data base?
Foreign key in what is java.
What is foreign key in SQL?
We use foreign key to match column in one table to primary key in column in another table either it is
one to one relation or many to one.This foreign key can be used to cross reference table.
Many database or data modelling will be in problem if relation of foreign key is not done properly.
In one table , it can be many foreign keys and it is independently by the database system.Each key can have
different reference tables.
What is foreign key in SQL?
We use foreign key to match column in one table to primary key in column in another table either it is
one to one relation or many to one.This foreign key can be used to cross reference table.
Many database or data modelling will be in problem if relation of foreign key is not done properly.
In one table , it can be many foreign keys and it is independently by the database system.Each key can have
different reference tables.
Wednesday, March 9, 2011
What is java Relational databases
What is java Relational databases
What is database?
We can store and retrieve information from place called database.
What is java in relational database?
Information that we present in tables as in row and column is called relational databases.
Relational means that the collections of objects with the same type in one rows.
We can relate data in table according to commons keys and retrieved data from table based on
relations.
What is Database Management Systems (DBMS)?
DBMS is responsible to handle the way data is stored , maintained , and retrieved.
What is database?
We can store and retrieve information from place called database.
What is java in relational database?
Information that we present in tables as in row and column is called relational databases.
Relational means that the collections of objects with the same type in one rows.
We can relate data in table according to commons keys and retrieved data from table based on
relations.
What is Database Management Systems (DBMS)?
DBMS is responsible to handle the way data is stored , maintained , and retrieved.
Sunday, March 6, 2011
What is java
Today i will discuss what is java in synchronization and how it is implemented, and it is important?
what is java in synchronization?
The Java programming language provides two basic synchronization idioms: synchronized methods and synchronized statements.
To make a method synchronized, simply add the synchronized keyword to its declaration:
public class SynchronizedCounter
{
private int c = 0;
public synchronized void increment()
{
c++;
}
public synchronized void decrement()
{
c--;
}
public synchronized int value()
{
return c;
}
}
If count is an instance of SynchronizedCounter, then making these methods synchronized has two effects:
* First, it is not possible for two invocations of synchronized methods on the same object to interleave. When one thread is executing a synchronized method for an object, all other threads that invoke synchronized methods for the same object block (suspend execution) until the first thread is done with the object.
* Second, when a synchronized method exits, it automatically establishes a happens-before relationship with any subsequent invocation of a synchronized method for the same object. This guarantees that changes to the state of the object are visible to all threads.
what is java in synchronization?
The Java programming language provides two basic synchronization idioms: synchronized methods and synchronized statements.
To make a method synchronized, simply add the synchronized keyword to its declaration:
public class SynchronizedCounter
{
private int c = 0;
public synchronized void increment()
{
c++;
}
public synchronized void decrement()
{
c--;
}
public synchronized int value()
{
return c;
}
}
If count is an instance of SynchronizedCounter, then making these methods synchronized has two effects:
* First, it is not possible for two invocations of synchronized methods on the same object to interleave. When one thread is executing a synchronized method for an object, all other threads that invoke synchronized methods for the same object block (suspend execution) until the first thread is done with the object.
* Second, when a synchronized method exits, it automatically establishes a happens-before relationship with any subsequent invocation of a synchronized method for the same object. This guarantees that changes to the state of the object are visible to all threads.
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