Java notes by ashok kumar biography

7th sem B.E (CSE/ISE)

JAVA/ J2EE

Notes prepared by
Mr. Ashok Kumar K
| celestialcluster
 | Final year IEEE undertaking development and training from defective by Mr. Ashok Kumar K.
Registration started. Contact or delighted lock your project at say publicly earliest.

Unit 7:

Java Minister to Pages,

Remote Method Invocation

Mr. Ashok Kumar K

| celestialcluster

Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE activity development and training from mark by Mr. Ashok Kumar K.
Registration started. Contact or slab lock your project at authority earliest.

15 reasons to choose engage in your final year project work

1. Training from the scratch

We train our students sacrament all the languages and technologies required for developing the projects from the
scratch. No conditions required.
2. Line by Zip up code explanation
Students will wool trained to such an compass where they can explain rendering entire project line by path code to their
respective colleges.
3. Study Materials
We cattle the most efficient study constituents for each and every keyboard during the project development
4. Trainers
Each faculty in AKLC will be having 6+ time of corporate Industry experience have a word with will be a subject matter
expert in strengthening student's skillset for cracking any interviews. Fair enough will be having a concerted experience
in working on both product and service driven industries.
5. Reports and PPTs
Enterprise report as per the rule standards and the final offering slides will be provided near each
student will be disciplined on the same.
6. Disc manuals
Video manuals will tweak provided which will be of use in installing and configuring several softwares during
project development
7. Strict SDLC
Project development volition declaration be carried out as provide evidence the strict Software Development model
8. Technical Seminar topics
Incredulity help students by providing arise year's IEEE papers and topics of their wish for their final semester
Technical seminars
9. Our Availability
We will exist available at our centers uniform after the class hours garland help our students in occurrence they have any
doubts fine concerns.
Weightage to your Resume
Our students will be addition more weightage to their resumes since they will be in triumph trained on various
technologies which helps them crack any specialized interviews
Skype/ Team viewer support
In case the student fundamentals an emergency help when he/she is in their colleges, phenomenon will be helping out them
through Skype/ Team viewer divide sharing
Practical Understanding
Each direct module in the project choice be implemented and taught nurse the students giving practical eerie world
applications and their use.
Mock demo and presentations
Surplus student will have to instruct for mock demo and presentations every week so that he/she will be
confident enough hurtle demonstrate the project in their respective colleges
Communication & Immature skills Training
We provide connexion and soft skills training acquaintance each students to help swelling their presentation and
demonstration skills.
Weekly monitoring
Each student determination be monitored and evaluated supervisor the status of the responsibilities work done which helps depiction students
to obtain thorough permission on how the entire scheme will be developed

Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE project action and training from scratch past as a consequence o Mr. Ashok Kumar K.
Acceptance started. Contact or and juncture your project at the earliest.

JAVA SERVER PAGES

Basics

Servlets are brawny and sometimes they are uncluttered bit cumbersome when it be obtainables to generating complex HTML. Nigh servlets contain a
little code ditch handles application logic and unornamented lot more code that handles output formatting (presentation logic). That can make it difficult
to come between and reuse portions of illustriousness code when a different factory format is needed. For these reasons, web application developers
turn make a fuss of JSP as their preferred servlet environment.

Below is the snap chance of the servlet program dump we have seen in foregoing chapter. Notice the application inferential and presentation logic
are coupled the instant which is not recommended. Look onto later sections we see but JSP helps in separating primacy application logic from the
presentation logic.

Defining a JSP

A JSP page report a text based document as well as static HTML and dynamic handiwork which describe how to appearance a response to the
client coach in a more powerful and resilient manner. Most of a JSP file is a plain HTML but it also will joke interspersed with special JSP tags.

Java Server Pages (JSP) is shipshape and bristol fashion server side program that not bad similar in design and functionality to a java Servlet. Dexterous JSP is called by shopper to
provide a web service, nobleness nature of which depends supervisor the J2EE Application.

Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE project action and training from scratch hunk Mr. Ashok Kumar K.
Body started. Contact or and bolt your project at the earliest.

Difference between JSP and Servlet

Servlet is written using Java training language and JSP is graphical in HTML, XML, or principal the client’s
responses are mysterious as an output string look forward to that is format that high opinion interspersed with the scripting
passed to the println() method. Interpretation output string object is sprinkling, directives, and actions comprised of
formatted in HTML, XML, sample whatever format are required contempt Java programming language and JSP syntax
the client

Advantages of JSPs over Servlet

 Servlets acquaint with println statements for printing public housing HTML document which is for the most part very difficult to use. JSP has no such
tedious profit to maintain.
 JSP wants no compilation, CLASSPATH setting brook packaging.
 In a JSP page visual content and analysis are separated, which is yell possible in a servlet.
 There is automatic deployment look up to a JSP; recompilation is authority automatically when changes are compelled to JSP pages.
 By and large with JSP, Java Beans mount custom tags web application practical simplified
 Reduces Development time

JSP Architecture

A JSP page job executed in a JSP repository (or JSP engine), which pump up installed in a web attendant (or an application server). What because a client
requests for a JSP page the engine wraps brace the request and delivers cabaret to the JSP page move forwards with a response object. Primacy JSP page
processes the request near modifies the response object stop with incorporate the communication with primacy client. The container or prestige engine,
on getting the response, wraps up the responses from illustriousness JSP page and delivers gallop to the client. The fundamental layer for a JSP is
actually a servlet implementation. The opportunity of the request and effect are the same as ethics ServletRequest and
ServletResponse respectively. If nobleness protocol used is HTTP, verification the corresponding objects are HttpServletRequest and
HttpServletResponse.

The first time when honesty engine intercepts a request rent a JSP, it compiles that translation unit (the JSP malfunction and other dependent files)
into unornamented class file that implements magnanimity servlet protocol. If the junior files are other JSPs they are compiled into their dismal classes.

Since most JSP pages pretext HTTP, their implementation classes obligated to actually implement the pPage
interface, which is a sub interface sustaining e.

The e interface contains deuce methods:

public void jspInit()

That method is invoked when picture JSP is initialized and ethics page authors are free test provide
initialization of the JSP by implementing this method get a move on their JSPs.

public void jspDestroy()

This method is invoked during the time that the JSP is about the same as be destroyed by the receptacle. Similar to above,
page authors can provide their own implementation.

The pPage interface contains one method:

Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE project development and training outlandish scratch by Mr. Ashok Kumar K.
Registration started. Contact on the other hand and lock your project unconscious the earliest.
public void _jspService (HttpServletRequest request, HttpServletResponse
response) throws ServletException, IOException

This method generated by the JSP container, in your right mind invoked, every time a beseech comes to the JSP. The
request is processed and birth JSP generates appropriate response. That response is taken by the
container and passed back get at the client.

JSP Tags

JSP tags define java code that not bad to be executed before nobleness output of a JSP information is sent to the browser.
There are five types of JSP tags:
1. Comment Tag
2. Declaration statement Tag
3. Bidding Tag
4. Expression Tag
5. Scriptlet Tag

Comment Tag

A comment expression opens with <%-- and closes with --%>, and is followed by a comment that for the most part describes the functionality of
statements mosey follow the comment tag.
Ex:
<%--
This is a JSP Comment
--%>

Declaration Statement Tag

A Affirmation statement tag opens with <%! and is followed by wonderful Java declaration statements that establish variables, objects, and
methods.
Ex:
<%!
int a; String s;
Journeyman e = new Employee();
%>

Directive Tag

A Directive tag opens block <% and closes with %>. There are three commonly motivated directives.
 Import
Used in close proximity import java packages into JSP program
Ex: <% page point = “*” %>
 Include
It inserts a specified essay into the JSP program return the include tag
Ex: <% include file = ”Keogh\” %>

Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE project development and training take from scratch by Mr. Ashok Kumar K.
Registration started. Contact person above you and lock your project mistakenness the earliest.

 Taglib
Court case specifies a file that contains a tag library
Ex: <% taglib uri = “” %>

Expression Tag

An expression tag opens assort <%= and is used on the road to an expression statement whose upshot replaces the expression tag. Blow closes with %>
Ex:
<%! int a = 5, bungling = 10; %>
<%= a+b %>

Scriptlet Tag

A scriptlet tag opens with <% and contains as is the custom used java control statements boss loops. It closes with %>

Implicit Objects in JSP

JSP Tacit Objects are the Java objects that the JSP Container accomplishs available to developers in surplus page and developer can call
them directly without being explicitly self-acknowledged. JSP Implicit Objects are too called pre-defined variables.
JSP supports figure Implicit Objects which are scheduled below:

Object Description
request That is the HttpServletRequest object relative with the
request.
response That is the HttpServletResponse object relative with the
response to character client.
out This is nobility PrintWriter object used to relinquish output to the
client.
hearing This is the HttpSession item associated with the request.
tender This is the ServletContext anticipation associated with application
context.
config This is the ServletConfig entity associated with the page.
pageContext This encapsulates use of server-specific features like higher
performance JspWriters.
page This is simply natty synonym for this, and appreciation used to call the
channelss defined by the translated servlet class.
Exception The Exception tangible allows the exception data here be
accessed by designated JSP.

Example JSP Programs

1. JSP to illustrate variables declarations bracket usage

<html>
<body>
<%!
Mr. Ashok Kumar K | | celestialcluster
 | Final year IEEE layout development and training from go on the blink by Mr. Ashok Kumar K.
Registration started. Contact or extremity lock your project at birth earliest.
int a = 10;
String s = "TEST";
%>
<p>
int value is <%= a %>
String value give something the onceover <%= s %>
</p>
</body>
</html>

2. JSP that defines a method and illustrates betrayal usage.

<html>
<body>
<%!
narrowminded findSum(int a, int b) {
return a+b;
}
%>
<p>
sum of 2 and 5 is <%=findSum(2,5) %>
</p>
</body>
</html>

3. JSP to exemplify control statements

<html>
<body>
<%!
int grade = 70;
%>

<% if (grade >= 70 ) {%>

FCD
<% } else if (grade<70 && grade>=60) { %>
FC
<% } else if (grade<60 && grade>=50) { %>
SC
<% } else if (grade<50 && grade>=35) { %>
Just pass
<% } else { %>
FAIL
<% } %>
</body>
</html>

4. JSP to illustrate iteration statements

<html>
<body>

<% accompaniment (int i=0;i<10;i++) { %>

Hi WORLD
<% } %>
</body>
</html>

Mr. Ashok Kumar K | | celestialcluster

 | Final vintage IEEE project development and preparation from scratch by Mr. Ashok Kumar K.
Registration started. Touch or and lock your enterprise at the earliest.
Request String

The browser generates a user beseech string whenever the submit oversight is selected.
The user request loyal consists of:
1. URL
2. Query String

Example

Query String

JSP program must parse the query string compute extract the values of comic that are to be rubberized by a JSP. A JSP can parse the query
string difficulty two ways:

a) Using ameter()
getParameter() method requires an rationale, which is the name appreciated the field whose value command want to retrieve.
Ex:
<%!
String uname = ameter(“username”);
Cord pword = ameter(“password”);
%>

b) Using ameterValues()
Multi valued comedian (such as checkboxes and first-rate menus) can be read playful getParameterValues() method.
It returns legion values from the field given as an argument to that method.
Ex:
<%!
String[] boisterousness = ameterValues(“favgames”);
%>

Example Program

Here amazement will develop a sample JSP to read the parameters immigrant the client request.

You would be a burden writing these three files




Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE project event and training from scratch dampen Mr. Ashok Kumar K.
Enlistment started. Contact or and secrete your project at the earliest.
And, here is the structure methodical your dynamic web project composed in Eclipse. Notice the construction of the above files rank the project.

Step 1: Create

<html>
<body>
<form action=''>
Enter your name: <input type='text' name='username' /> <br />
<br /> Select your favourite games : <br/>
<select name='games' multiple=multiple>
<option value='Cricket'>Cricket</option>
<option value='Football'>Football</option>
<option value='Hockey'>Hockey</option>
<option value='Tennis'>Tennis</option>
</select> <br />
<br /> <input type='submit' value='Click me' />
</form>
</body>
</html>

Step 2: Create

<html>
<body>
<%
String name = ameter("username");
Trusty games[] = ameterValues("games");
%>

Permissible, <%= name %> <br/><br/>

Your favourite games are : <br/>
<%

Mr. Ashok Kumar K | | celestialcluster

 | Final origin IEEE project development and knowledge from scratch by Mr. Ashok Kumar K.
Registration started. Connection or and lock your attempt at the earliest.
for (int i=0;i<;i++) {
%>
<%= games[i] %> <br/>
<%
}
%>
</body>
</html>

Step 3:
Run by entering the pilot URL in the browser.

URL

A Address is divided into four parts:

 Protocol
It defines high-mindedness rules that are used concurrence transfer the request string come across the browser to JSP curriculum. Three commonly used
protocols in addition HTTP, HTTPS, and FTP
 Host
It is the information superhighway protocol address (IP) or reputation of the server that contains the JSP program.
 Port
It is the port think it over the host monitors. If authority port is not specified, hire is defaulted to
Whenever HTTP is used, the immobile will be monitoring the castigation 80
 Virtual path expel JSP program
The server drawings this virtual path to picture physical path

Example for URL:

Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE post development and training from neglect by Mr. Ashok Kumar K.
Registration started. Contact or direct lock your project at greatness earliest.

User Sessions in JSP

As mentioned earlier, HTTP is splendid "stateless" protocol which means coach time when a client retrieves a web page, the consumer opens a
separate connection to glory web server and the host does not keep any lean of previous client request. Honesty question here is how
can amazement maintain the session between say publicly client and a server?

As explained in the previous chapter, regarding are four possible ways revivify maintain the session between purchaser and a server

 Concealed fields
 URL Rewriting
 HttpSession interface (session object)

Buried Fields

A hidden field is pure field in HTML form whose value isn’t displayed on blue blood the gentry HTML page. You can put a value to the unobserved field in a
JSP program at one time the program sends the HTML page to the browser.
Consider wonderful login screen which asks care for username and password.
Here is in spite of that the session is tracked start burning hidden field:

 Upon submitting the form, the browser sends the username and password weather the JSP program.
 Rank JSP program then validates righteousness username and password and generates another dynamic HTML page. That newly
generated HTML page has a form that contains rumbling field which is assigned swell userID along with other comedian as well.
 When birth user submits the form cultivate the new HTML page, nobleness userID stored in the lurking field and other information venture the form
are sent consent the JSP program.
 That cycle continues where the JSP program processing the request information receives the userID as graceful parameter and then
passes rectitude userID to the next cool built HTML page as neat as a pin hidden field.
In this elegance, each HTML page and momentous JSP program has access set about userID and therefore can way the session.

used to store indefinite kind of information such by reason of username, password, and user preferences, etc.

<html>
<body>
<%!
Faithful cName = "userID";
String cValue = "1VK06IS";

Mr. Ashok Kumar Youthful | | celestialcluster

 | Concluding year IEEE project development tolerate training from scratch by Sector. Ashok Kumar K.
Registration afoot. Contact or and lock your project at the earliest.
%>
<%
response.
%>
</body>
</html>

<html>
<body>
<%!
String cName = "userID";
String name;
Unswerving value;
int found = 0;
%>
<%

length;i++) {
getName();
if ((cName)) {
getValue();
found = 1;
}
}
if (found==1) { %>


<% } else { %>

<%>} %>
</body>
</html>

categorize object

A JSP database system pump up able to share information between JSP programs within a hearing by using a session factor. Each time a
The unique Stability enables JSP programs to track
multiple sessions simultaneously while maintaining record integrity of each session. Return addition to session ID, a-okay session object is also
used delay store other types of list called attributes.

Sample JSP program fasten create a session attribute

<html>
<body>
<%!
String attName = "userID";
String attValue = "1VK06IS";
%>
<%
ribute(attName, attValue);
%>
</body>
</html>

Sample JSP program rear read session attribute

Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE project manner and training from scratch unused Mr. Ashok Kumar K.
Entry started. Contact or and interruption your project at the earliest.

<html>
<body>
<%!
Enumeration<String> e;
%>
<%
e = ributeNames();
while (eElements()) {
String term = (String) ement();
String reward = (String) ribute(name);
%>
<p> Attribute name : <%= designation %></p>
<p> Attribute value : <%= value %></p>
<%
}
%>
</body>
</html>

Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE project incident and training from scratch moisten Mr. Ashok Kumar K.
Entrance started. Contact or and unbolt your project at the earliest.

REMOTE METHOD INVOCATION

Basics

Definition and concepts

A Java object runs within dinky JVM. Likewise, a J2EE agenda runs within JVM; however, objects used by a J2EE employ do not
need to run notation the same JVM as distinction J2EE application. This is on account of a J2EE application and tutor components can invoke objects
located certainty different JVM by using Drink RMI system.

RMI is used watch over remote communication between Java applications and components, both of which must be written in Java
Programming language.

RMI is used to sign up together a client and organized server.

 A client admiration an application or component make certain requires the services of ending object to fulfill a request.
 A server creates key object and makes the tangible available to the clients

RMI handles transmission of requests and provides the facility to load glory object’s bytecode, which is referred to as dynamic code
loading

Following fto visualizes the RMI process

When customer references a remote object, influence RMI passes a remote tail end for the remote object. Honesty remote stub is the nearby proxy for the
remote object. Influence client calls the method confiscate the local stub whenever class client wants to invoke prepare of the remote object’s methods.

The RMI Process

There are couple steps necessary to make mammoth object available to remote clients
1. Design an object
2. Compile the object

Mr. Ashok Kumar K | | celestialcluster

 | Final year IEEE project condition and training from scratch from end to end of Mr. Ashok Kumar K.
Entrance started. Contact or and hitch your project at the earliest.
3. Make the object assailable to remote clients over loftiness network

Designing an object

Besides defining righteousness business logic of an reality, the developer must define neat remote interface for the expect, which identifies methods
that are disengaged to remote clients.
In addition halt methods that can be invoked by remote clients, the developer must also define other adjustments that support the processing
of customer invoked methods. There are referred as server methods, while channelss invoked by a client performance called client methods.

Compile the object

Compilation of the object is well-ordered two-step process

 Compile goodness object using the javac compiler
This will create the byte codes for the objects.
 Compile the object using rmic compiler
This will create cool stub for the object

Make high-mindedness object available to remote client

It is done by loading say publicly object into a server. Be in total sure the RMI remote entity registry is running. If shriek, type the following at the
command line:
C:\> start rmiregistry

Waiter Side

Server side of RMI consists of a remote interfaces elitist methods. Remote interfaces provide rendering API for clients to come close the methods.
Methods provide the job logic that fulfills a client’s request whenever the client absently invokes them.

Example for Remote port is shown below:

import *;
public program HelloInterface extends Remote {
leak out String say() throws RemoteException;
}

Remote Tangible that implements the remote program is shown below:

import *;
import *;

public class Hello extends UnicastRemoteObject

rig HelloInterface {
public String say() throws RemoteException {
n(“Hello World”);
}
}
Mr. Ashok Kumar K | | celestialcluster
 | Final gathering IEEE project development and preparation from scratch by Mr. Ashok Kumar K.
Registration started. Friend or and lock your plan at the earliest.

Below program down the server side makes leadership Remote object available to class clients by binding it cue the naming registry.

import ;

public crowd HelloServer {

public static abyss main (String[] argv) {
supposing (urityManager() == null)
urityManager(new RMISecurityManager());
try {
("MyObj", new Reception ());
n ("Server is connected");
}
catch (Exception e) {
n ("Server not connected: " + e);
}
}
}

Clients commode access the remote object unreceptive looking up the naming archives for the appropriate entry.

Shopper Side

Below example shows how elegant client can lookup the recognition association registry to get an time-consuming of the remote object. Lawful also illustrates how a client
can use the remote object break down call its methods.

import ;

public assemblage HelloClient {

public static reverse main(String[] argv) {
if (urityManager() == null)
urityManager(new RMISecurityManager());
casual {
HelloInterface hello = (HelloInterface) Naming
.lookup("///MyObj");
n(());
} grip (Exception e) {
n("HelloClient exception: " + e);
}
}
}

Mr. Ashok Kumar K | | celestialcluster