init

Why do we need an init() method in servlet? Can't we use the constructor to initialization? Because Servlet is an interface, not an abstract class. Constructor arguments cannot be specified on an interface, so the ServletContext needs to be specified on a normal method signature. This allows the application server to know how to initialize any Servlet implementation properly. Another solution would have been to require, but not enforce at compile time, a constructor taking ServletContext. The application server would then call the constructor via reflection. However, the designers of the

In the constructor of an Array is there a guarantee that the init function will be called for the indexes in an increasing order? It would make sense but I did not find any such information in the docs: https://kotlinlang.org/api/latest/jvm/stdlib/kotlin/-array/-init-.html#kotlin.Array%24 %28kotlin.Int%2C+kotlin.Function1%28%28kotlin.Int%2C+kotlin.Array.T%29%29%29%2Finit leonardkraemer There is no guarantee for this in the API. TLDR: If you need the sequential execution, because you have some state that changes see bottom. First lets have a look at the implementations of the initializer:

为了学习linux，最近一直看鸟哥的私房菜，很适合入门的一本书，不过我装的发行版本是 Fedora 19 ，而不是 CentOs ，因为不知道什么原因卡在分区哪里，不过这些都无所谓，每个发行版本本质区别其实并不大，毕竟用的是一样的kernel。 不过还是有一些区别的，所以以下记录都是从Fedora 19的KDE桌面环境出发的。 1.X Window 与 命令行模式的切换 命令行模式也被称为终端界面(terminal 或 console)。 Linux默认的情况下会提供6个Terminal来让用户登陆，切换的方式是 [Ctrl] + [Alt] + [F1]~[F6] 的组合按钮。系统会将 [F1]~[F6] 命名为tty1~tty6的操作界面环境： [Ctrl] + [Alt] + [F1]~[F6]：文字界面登录 tty1~tty6 终端； [Ctrl] + [Alt] + [F7]：图形界面桌面； 不过在 Fedora 19 的KDE环境中 [F1] 才是图形界面， [F2]~[F6] 是文字界面，至于 [F7 ] 是什么界面就不知道了。 2.X Window下进入命令行模式和命令行模式进入X Window模式 在纯文本环境 下执行如下命令即可： startx 在图形界面模式下执行如下命令： [Ctrl] + [Alt] + [Backspace] 即可kill掉X

In C#/Winforms how do I set the default focus when my application starts? Mehrdad Afshari The one with the minimum tab index automatically gets the focus (assuming the TabStop property is set to true). Just set the tab indices appropriately. By the way, Visual Studio provides a way to easily set tab indices by just clicking on the controls in the order you want. You can activate this feature by choosing "Tab Order" option in the "View" menu when you are in the form design view. You can also manually give the focus to a control by calling its Select method when the form loads. 来源： https:/

In drivers I often see these three types of init functions being used. module_init() core_initcall() early_initcall() Under what circumstances should I use them? Also, are there any other ways of init? They determine the initialization order of built-in modules. Drivers will use device_initcall (or module_init ; see below) most of the time. Early initialization ( early_initcall ) is normally used by architecture-specific code to initialize hardware subsystems (power management, DMAs, etc.) before any real driver gets initialized. Technical stuff for understanding below Look at init/main.c .

I made a subclass of UIView that has a fixed frame. So, can I just override init instead of initWithFrame: ? E.g.: - (id)init { if ((self = [super initWithFrame:[[UIScreen mainScreen] bounds]])) { self.backgroundColor = [UIColor clearColor]; } return self; } The Xcode documentation for -initWithFrame: says: "If you create a view object programmatically, this method is the designated initializer for the UIView class. Subclasses can override this method to perform any custom initialization but must call super at the beginning of their implementation." What does "designated initializer" mean?

In Objective-C, what is the difference between the init method (i.e. the designated initializer for a class) and the initialize method? What initialization code should be put in each? -init is an instance method, used to initialize a particular object. +initialize is a class method, run before any instances of the class are created and before other class methods are run. +initialize isn't something you use most of the time, but it's handy for setting up any static variables that the class as a whole might use, or for ensuring that certain conditions are met before any instances are created.

Servlet的生命周期过程: (1) 从始至终,在Servlet提供整个服务的过程当中,服务器内部只有一个Servlet对象. (2)加载ClassLoader (3)实例化 new : 在客户端第一次访问的时候,tomcat会为其new一个实例出来. (4)init(Servlet Config) : 此方法只调用一次,做初始化工作,只需把方法写好等待即可,tomcat会在适当的时机去调用词方法. (5)处理请求 (Service doGet doPost):以多线程的方式执行. (6)退出服务 destroy(): 当servlet退出服务的时候,也就是web应用程序退出或者重新加载tomcat的时候,Servlet的生命周期就结束了. View Code import java.io.IOException; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; // 演示了Servlet的生命周期 /** * (1)在整个生命周期中,在服务器的内部,只有一个Servlet对象 *