Create First Program
In this section, you will learn to write a simple
Java program. For developing a java program you just need a simple text editor
like "notepad".
Open the notepad and write your program.
Let's create a class createfirstprogram that will print a
message "Welcome to RoseIndia.net" on the console.
Here is the code of createfirstprogram.java file:
class createfirstprogram{
public static void main(String[] args) {
System.out.println("Welcome to RoseIndia.net");
}
}
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Download this example.
Save this program in the specified directory ("C:\Vinod"
in this example) with name createfirstprogram.java.
This class contains public, static and
void java keywords (these are pre-defined words in java which
carries specific meaning).
public keyword specifies the
accessibility issues of a class. Here, It specifies that method can be accessed from anywhere.
static keyword indicates that this method can be invoked simply by using
the name of the class without creating any class-object.
void keyword specifies that this method will not return any type of data.
main() method is the main entry point of the
program, to start execution. First of all JVM
calls the main method of a class and start execution . JVM
(Java Virtual Machine) is responsible for running java programs.
args is a string array that takes values from java
command line. It's index starts from '0'. We can access values by writing
args[0], args[1] etc.
println() function prints the output to the standard output stream
(monitor).
out represents the standard output stream (monitor).
Now, you are ready to compile and run this
program. Open the command prompt and go to the directory ("C:\vinod"
in this example) where your program is saved.
Java uses the "javac"
command to compile your program (Type javac createfirstprogram.java) . After compiling
successfully, you can run it.
Java uses the "java"
command to execute your program (Type java createfirstprogram). It will print "Welcome to
RoseIndia.net".
Output of program:
C:\vinod>javac
createfirstprogram.java
C:\vinod>java createfirstprogram
Welcome to RoseIndia.net
C:\vinod>_ |
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Current Comments
6 comments so far (post your own) View All Comments Latest 10 Comments:i was amazed when i had seen such a good lucid understanding site with all the java stuff its really amazing world to learn!!!!
Posted by RAKESH.S on Wednesday, 05.21.08 @ 16:09pm | #60592
This didn't tell me anything and the program didn't work!
Posted by Marty on Monday, 04.28.08 @ 07:18am | #58026
in java how to connect two forms without making any validation. pls if possible send me the code. its very urgent.
Posted by varsha on Saturday, 03.29.08 @ 23:58pm | #54682
Hi
Really very useful
Posted by shoby on Saturday, 01.19.08 @ 16:15pm | #45586
Hi, ur tutorial is great.
I got a doubt:If i created class files of 2 objects A and B and given the main method in class A, can i declare methods related to B object In class A and execute them .kindly provide me a solution to this question.
Thank u
Posted by srinivas on Thursday, 10.18.07 @ 12:32pm | #34322
The program is working for me
Posted by skhumba20 on Friday, 09.28.07 @ 14:29pm | #30138