- what is Abstraction?
Abstraction is a process of hiding the implementation details and showing only functionality to the user. Another way, it shows only important things to the user and hides the internal details for example sending sms, you just type the text and send the message. You don’t know the internal processing about the message delivery.
- Abstract Class
A class which contains the abstract keyword in its declaration is known as abstract class.
- Abstract classes may or may not contain abstract methods, i.e., methods without body ( public void get(); )
- But, if a class has at least one abstract method, then the class must be declared abstract.
- If a class is declared abstract, it cannot be instantiated.
- To use an abstract class, you have to inherit it from another class, provide implementations to the abstract methods in it.
- If you inherit an abstract class, you have to provide implementations to all the abstract methods in it.
Java servlet is a Java program that extends the capabilities of server.It is used to create web application.
Servlets provide a component-based, platform-independent method for building Web-based applications, without the performance limitations of CGI programs. Servlets have access to the entire family of Java APIs, including the JDBC API to access enterprise databases.
More about Servlet….
Exception handling in java
What is an exception?
An Exception can be anything which interrupts the normal flow of the program. When an exception occurs program processing gets terminated and doesn’t continue further. In such cases we get a system generated error message. The good thing about exceptions is that they can be handled. We will cover the handling part later in this same tutorial.
Explore more about exception Exception Handling
Java App let
Applet are the special program which are embedded in the web page to generated dynamic content.It runs inside the browser and works at client side.
Some feature are :
- It works at client side so less response time.
- It can be executed by browsers running under many platforms.
Some Few point make sense for applet are Graphics – java.awt.Graphics class provides many methods for graphics programming. Read More
JVM – Platform Independency
JVM Stands for Java Virtual Machine, One of the most important feature java developer comes up.it is an interpreter which accepts ‘Bytecode’ and executes it.
Java has been termed as a ‘Platform Independent Language’ as it primarily works on the notion of ‘compile once, run everywhere’. Here’s a sequential step establishing the Platform independence feature in Java
Java JVM architecture diagram JVM Architecture Explaination