set environment variables and first java program in
detailed
1. Set Permanent path:
Go
to MyComputer properties à advanced tab Ã
environment variables à new tab of user
variable à write path in variable name Ã
write path of bin folder in variable value
à ok Ã
ok à ok.
1. Right click
on MyComputer and select Properties
2. Click on
Advanced system settings
3. Click on
Environment Variables
4. Click on
New in user variables
5. Copy bin
folder path
6. Write “path”
in variable name and past the path of bin folder.in variable value and click on
“ok”.
7. Click on “ok”
8. Click on “ok”
1. Temporary path:
Copy the bin path and past it in
command prompt as
“set path= C:\Program Files\Java\jdk1.6.0\bin”
Here I set temporary path for D
driveà programs folder because I save
all my programs in that folder.
First java program in detailed:
public class Test
{
public static void main(String[] arg)
{
System.out.println("This is my first java program");
}
}
Open notepad and write the above program
I saved that program as “Test.java” in drive DÃ programs folder
Compile it “javac Test.java” and after compiled it, created
a .class file
Run that .class file as “java Test” command
Explanation:
public class Test
public keyword is an access modifier, it mean other
classes can access this class.
class is a keyword to declare the class name.
“Test” is a class name
of this program.
{ open brace, it mean
starting of the class scope.
public static void main(String[] arg)
static is a keyword. If we declare a method as
static, no need to create object for that method. Here no need to create object
to invoke main method. The main method is executed by JVM.
void is return type. It does not return any
value.
“main” is a method name.
It represents startup of the program.
(String[] arg) is main method parameter, it stores the values as String array format “arg” is a variable, we can give other name
whatever we want(a[],b[],ect..).
Example:
String a=arg[0];
String b=arg[1];
{ open brace for main
method.
System.out.println("This is my first
java program");
System is a class in the java.lang package.
“out” is a static member
of the System class
“println” is a method of
the java.io.PrintStream
} close main method
} close class
Execution:
Save the above program as: “Test.java”
Compile: javac “Test.java”
Execution: java “Test.java”
Output: This is my first java
program
