Skip to main content

JSP Lifecycle

JSP Lifecycle



The lifecycle of a JSP is the entire process from its creation till the destruction which is similar to a servlet life cycle with an additional step, which translates the JSP into a Servlet.
Following are the JSP Lifecycle phases.
1.     Translation of JSP to Servlet code.
2.     Compilation of Servlet to bytecode.
3.     Loading Servlet class.
4.     Creating servlet instance.
5.     Initialization by calling jspInit() method
6.     Request Processing by calling _jspService() method

7.     Destroying by calling jspDestroy() method
JSP Lifecycle
JSP Lifecycle

JSP Translation and Compilation
When a user request for a JSP, the JSP engine first checks to see whether it needs to compile the page. If the page has never been compiled, or if the JSP has been modified since it was last compiled, the JSP engine does the following
1.   Parse the JSP
2.   Transforms the JSP to a Servlet
3.   Compile the Servlet (.java) file to a class file.


JSP Initialization
Before servicing any request the web container loads the JSP and invokes jspInit() method. Initialization is performed only once, just as with servlets init() method. If you need to perform any JSP-specific initialization, you need yo override the jspInit() method.

JSP Service
Once the JSP page has been loaded and initialized, the JSP engine invokes the _jspService() method in the JSP.
The _jspService() method takes an HttpServletRequest and an HttpServletResponse as its parameters.
The _jspService() method of a JSP is invoked once per request and is responsible for generating the response for that request.

JSP Destruction
The destruction phase of the JSP life cycle represents when a JSP is being removed from use by a container.
The jspDestroy() method is the JSP similar to the destroy method for servlets. We need to Override jspDestroy() method when we need to perform any cleanup operation, such as releasing database connections or closing files which were opened

Comments

Post a Comment

Popular posts from this blog

Mockito interview Questions

1.       Question 1. What Is Mockito? Answer : Mockito allows creation of mock object for the purpose of Test Driven Development and Behavior Driven development. Unlike creating actual object, Mockito allows creation of fake object (external dependencies) which allows it to give consistent results to a given invocation. 2.       Question 2. Why Do We Need Mockito? What Are The Advantages? Answer : Mockito differentiates itself from the other testing framework by removing the expectation beforehand. So, by doing this, it reduces the coupling. Most of the testing framework works on the "expect-run-verify". Mockito allows it to make it "run-verify" framework. Mockito also provides annotation which allows to reduce the boilerplate code. 3.       Question 3. Can You Explain A Mockito Framework? Answer : In Mockito, you always check a particular class. The dependency in that class is injected using m...
2 comments
Read more

JAVA Expert Interview Questions Answers 2017

Java Basics ::  Interview Questions and Answers Home  »  Interview Questions  »  Technical Interview  »  Java Basics  » Interview Questions 1.     What is the difference between a constructor and a method? A constructor is a member function of a class that is used to create objects of that class. It has the same name as the class itself, has no return type, and is invoked using the new operator. A method is an ordinary member function of a class. It has its own name, a return type (which may be void), and is invoked using the dot operator. 2.     What is the purpose of garbage collection in Java, and when is it used? The purpose of garbage collection is to identify and discard objects that are no longer needed by a program so that their resources can be reclaimed and reused. A Java object is subject to garbage collection when it becomes unreachable to the program in which it is used. 3.  ...
3 comments
Read more

Java Example Program to Convert List to Set

import java.util.ArrayList; import java.util.HashSet; import java.util.Set; public class ListToSet {  /**   * @author Amarjit Kumar   * @category interview questions   *   * Description: Convert List to set in java with example program   *   */  public static void main(String[] args) {   ArrayList<String> arrList= new ArrayList<>();   arrList.add("Java");   arrList.add("Java");   arrList.add("List to String");   arrList.add("Example Program");   Set<String> strSet = new HashSet<String>(arrList);   System.out.println(strSet);   System.out.println(arrList);  } } /*  * Java program to convert list to set. Convert ArrayList of string to HashSet  * in java example program How to convert List to Set in java Set<String> strSet  * = new HashSet<String>(arrList); HashSet having a constructor which will take  * list as an ar...
Post a Comment
Read more