Hello everybody… Today we are going to start a new journey with java programming. I think you know about this programming little. If you are a fresher in java then please comment here for the beginning parts.
When we consider a Java program, it can be defined as a collection of objects that communicate via invoking each others methods. Let us now briefly look into what do class, object, methods and instance variables mean.
- Object – Objects have states and behaviors. Example: A dog has states-color, name, breed as well as behaviors -wagging, barking, eating. An object is an instance of a class.
- Class – A class can be defined as a template/blue print that describes the behaviors/states that object of its type support.
- Methods – A method is basically a behavior. A class can contain many methods. It is in methods where the logic are written, data is manipulated and all the actions are executed.
- Instance Variables – Each object has its unique set of instance variables. An object’s state is created by the values assigned to these instance variables.
First Java Program:
Let us look at a simple code that would print the words Hello World.
public class My_First_Java_Program {
/* This is my first java program.
* This will print ‘Hello World’ as the output
*/
public static void main(String[]args){
System.out.println(“Hello World”);// prints Hello World
}
}
Let’s look at how to save the file, compile and run the program. Please follow the steps given below:
- Open notepad and add the code as above.
- Save the file as: MyFirstJavaProgram.java.
- Open a command prompt window and go o the directory where you saved the class. Assume it’s C:\.
- Type ‘ javac MyFirstJavaProgram.java ‘ and press enter to compile your code. If there are no errors in your code, the command prompt will take you to the next line(Assumption : The path variable is set)
- If you are using eclipse then you will get the run-time environment there and get the built in compiler there just save that file in the project and run this by pressing ctrl+F11
Thatz all for today now try it.
By the way I have my own blog now. I am going to start it with some tricks and hacks of programming and technology. If you wish to visit there please click here. Or visit blog.techiehunter.org
