What is init () method in Java?
In Java, an initializer is a block of code that has no associated name or data type and is placed outside of any method, constructor, or another block of code. Java offers two types of initializers, static and instance initializers.
How many Init methods are there in servlet?
There are 5 methods in Servlet interface. The init, service and destroy are the life cycle methods of servlet. These are invoked by the web container.
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Methods of Servlet interface.
| Method | Description |
|---|---|
| public ServletConfig getServletConfig() | returns the object of ServletConfig. |
What is Init method called?
__init__ is one of the reserved methods in Python. In object oriented programming, it is known as a constructor. The __init__ method can be called when an object is created from the class, and access is required to initialize the attributes of the class.
What is init parameter in servlet?
The init-param element within a filter or servlet definition element contains initialization parameters for that filter or servlet instance. These are distinct from context parameters, discussed in Section 4.7. Each init-param contains a param-name element and a param-value element.
What is the __ init __ method used for?
The __init__ function is called every time an object is created from a class. The __init__ method lets the class initialize the object’s attributes and serves no other purpose. It is only used within classes.
Which init () method of servlet will be executed?
The init() Method
The init method is called only once. It is called only when the servlet is created, and not called for any user requests afterwards. So, it is used for one-time initializations, just as with the init method of applets.
How many types are there in servlet?
There are two main types of Servlet. They are Generic and HTTP servlets. We can use the constructor method to initialize the Servlets with the help of init() and the destructor method to remove the servlet from the resources using destroy().
What is the difference between GenericServlet and HttpServlet?
The main difference between GenericServlet and HttpServlet is that the GenericServlet is protocol independent and can be used with any protocol such as HTTP, SMTP, FTP, and, CGI while HttpServlet is protocol dependent and only used with HTTP protocol.
What is def __ init __( self?
In this code: class A(object): def __init__(self): self.x = ‘Hello’ def method_a(self, foo): print self.x + ‘ ‘ + foo. the self variable represents the instance of the object itself. Most object-oriented languages pass this as a hidden parameter to the methods defined on an object; Python does not.
What is init-param?
init-param. This is an element within the servlet. The optional init-param element contains a name/value pair as an initialization parameter of the servlet. Use a separate set of init-param tags for each parameter. You can access these parameters with the javax.
How can you create and initialize a servlet?
Use the @WebServlet annotation to define a servlet component in a web application. This annotation is specified on a class and contains metadata about the servlet being declared. The annotated servlet must specify at least one URL pattern.
What is __ init __? Give the example?
“__init__” is a reseved method in python classes. It is called as a constructor in object oriented terminology. This method is called when an object is created from a class and it allows the class to initialize the attributes of the class.
How many times init () destroy () service () method will be invoked?
This method accepts two parameters. destroy() method : The destroy() method is called only once. It is called at the end of the life cycle of the servlet.
Can we override Init method in servlet?
init(ServletConfig) or simply override the init() method that takes no arguments. This your servlet’s ServletConfig enables be saved locally and later returned by calls to your servlet’s getServletConfig() method. This method enables other servlet methods to access the variable.
What are two main types of servlet?
There are two main servlet types, generic and HTTP:
- Generic servlets. Extend javax. servlet. GenericServlet. Are protocol independent.
- HTTP servlets. Extend javax. servlet. HttpServlet. Have built-in HTTP protocol support and are more useful in a Sun Java System Web Server environment.
What is life cycle of servlet?
There are three life cycle methods of a Servlet : init() service() destroy()
What is the difference between doGet () and doPost () in servlet?
->doGet() shall be used when small amount of data and insensitive data like a query has to be sent as a request. ->doPost() shall be used when comparatively large amount of sensitive data has to be sent. Examples are sending data after filling up a form or sending login id and password.
What is difference between ServletConfig and ServletContext?
The servletconfig object refers to the single servlet whereas servletcontext object refers to the whole web application. ServletConfig is implemented by the servlet container to initialize a single servlet using init(). That is, you can pass initialization parameters to the servlet using the web.
What is __ init __? Explain with example?
The __init__ method is the Python equivalent of the C++ constructor in an object-oriented approach. The __init__ function is called every time an object is created from a class. The __init__ method lets the class initialize the object’s attributes and serves no other purpose. It is only used within classes.
What is filter in servlet?
The Java Servlet specification version 2.3 introduces a new component type, called a filter. A filter dynamically intercepts requests and responses to transform or use the information contained in the requests or responses.
How servlet is created?
The servlet example can be created by three ways: By implementing Servlet interface, By inheriting GenericServlet class, (or) By inheriting HttpServlet class.
What is the purpose of __ init __ method?
What is the lifecycle of a servlet?
Can a constructor be used in place of init () method to initialize a servlet?
The short answer to this question, Yes, Servlet implementation classes can have a constructor but they should be using the init() method to initialize Servlet because of two reasons, first you cannot declare constructors on an interface in Java.
Is servlet thread safe?
By default, servlets are not thread-safe. The methods in a single servlet instance are usually executed numerous times simultaneously up to the available memory limit. Each execution occurs in a different thread, though only one servlet copy exists in the servlet engine.