JEE

JEE stands for Java Enterprise Edition. JEE can use for business, web, client and information applications.

JEE Applications

Web components - JSP,Servlets
Web services - JAX/WS, JAX/RS
Data access in Java - JDBC/JPA
Persist and entities and enterprise Java beans

To create JEE project in Eclipse

Create Dynamic Web Project
Under the web contents create your web pages (html files)

You can use Apache Tomcat server to deploy your web application.

To change URL

To change the URL of servlets that you have built, you have to configure web.xml file.

As an example, you have to add following lines to your web.xml file

<servlet>
<servlet-name>helloworld</servlet-name>
<servlet-class>com.amali.surverlet.HelloWorld</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name> helloworld</servlet-name>
<url-pattern>/hidden/hello.do</url-pattern>
</servlet-mapping>

If user want to redirect pages without changing URL: they can use RequestDisptacher

Manually Deploy applications

Go to webapps folder in tomcat installation directory
Create a new folder
Copy META-INF and WEB-INF folders from your project folder to the newly created folder
Goto WEB-INF folder and copy classes folder (build-> classes) from project folder
Start the tomcat server

You can build a war file and copy it to webapps folder.Then you can run your application in tomcat server.

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Object Oriented Programming (OOP)

Object Object is an entity that has state and behavior Class Collection of objects is known as class. There are four main types of OOP concepts Inheritance Object acquire all the properties and behavior of parent object Improve code re-usability Polymorphism One task is performed by different ways Use method overload and override Abstraction Hiding internal details and showing functionality Use abstract class and interfaces Encapsulation Binding code and data into a single unit

Sorting Algorithms

Bubble Sort Named as sinking sort. Compare each pair of the adjacent items and swap them if they are in the wrong order. Worst case and average case time complexity both O(n^2) and best case time complexity is O(n).

Java-8

Java 8 New Features There are several new features added in Java 8 version. Some of the important new features are: Define methods inside the interface For each method Lambda Expression Stream API DateTime API 1) Define methods (default, static) inside the Interface After you published your interface, you can't change it by adding some abstract methods. But if you want to add methods you can define those methods inside the interface. Therefore Java 8 support default and static methods inside the interface. In Java 7 version interface only have abstract methods (no method implementation) and an abstract class can have both abstract and non-abstract methods. In Java 8 version you can add method implementation in the interface, but you have to declare that method as default method. ex: default void show(){............} To avoid diamond problem you have to override the method in implementation class if two interfaces have same default method ...

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