Technology Questions

Error-first callbacks are used to pass errors and data as well. You have to pass the error as the first parameter, and it has to be checked to see if something went wrong. Additional arguments are used to pass data.

fs.readFile(filePath, function(err, data) {
if (err) {
// handle the error, the return is important here
// so execution stops here
return console.log(err)
}
// use the data object
console.log(data)
})

In general, Services are Javscript functions and are responsible to do a specific tasks. Factories implements module pattern in which we use a factory method to generate an object which is use for building models.

It's syntax is
module.factory('factoryName', function);

There is no difference between int and int32. System. Int is an alias name for System.Int32 which is a .Net Class.

Type 4  (JDBC Net pure Java Driver) is the fastest JDBC driver.  Type 1 and Type 3 drivers will be slower than Type 2 drivers (the database calls are make at least three translations versus two), and Type 4 drivers are the fastest (only one translation).

A PHP Session persist the user information to be used later. For example, user name, password, shopping item details. The session is temporary and will be removed soon after the user has left the web site. The session can be persisted for long term usage on databases like MySQL. Each session is identified by a unique Id number for every visitor. The first step to use PHP session is to start the session. The starting session must precede the operations like HTML or the other.

The statement session_start() starts the PHP session and registers the user’s information on the server.

The Spring Beans are Java Objects that form the backbone of a Spring application. They are instantiated, assembled, and managed by the Spring IoC container. These beans are created with the configuration metadata that is supplied to the container.
Beans defined in spring framework are singleton beans. There is an attribute in bean tag named "singleton" if specified true then bean becomes singleton and if set to false then the bean becomes a prototype bean. By default it is set to true. So, all the beans in spring framework are by default singleton beans.