Hello Java Program
13:10:00
Hello java program is first program in java. Its very easy coding , you can get idea about how to type program and save with java extension. then compile and execute it.
Step 1:
Download: Text editor like Note pad or Notepad ++ (N++ recomended)
Step 2:
Type your program in text editor then save with classname.java extension under one foldre, its called directries.
Step 3:
Goto cmd then point your folder( eg: cd.. and cd..finaly get c drive then cd folder name. then type
for compile : javac ProgramName.java
for execute : java ProgramName
Step 1:
Download: Text editor like Note pad or Notepad ++ (N++ recomended)
Step 2:
Type your program in text editor then save with classname.java extension under one foldre, its called directries.
Step 3:
Goto cmd then point your folder( eg: cd.. and cd..finaly get c drive then cd folder name. then type
for compile : javac ProgramName.java
for execute : java ProgramName
Java programming source code
"Hello World" is passed as an argument to println method, you can print whatever you want. There is also a print method which doesn't takes the cursor to beginning of next line as println does. System is a class, out is object of PrintStream class and println is the method.
Output of program: Hello World
Note :
When we consider a Java program, it can be defined as a collection of objects that communicate via invoking each other's 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 behavior
such as wagging their tail, barking, eating. An object is an instance of a
class.
·
Class − A class can be defined as a
template/blueprint that describes the behavior/state that the object of its
type supports.
·
Methods − A method is basically a
behavior. A class can contain many methods. It is in methods where the logics
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 will print the words Hello World.
Example:
public class MyFirstJavaProgram {
/* 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
subsequent steps
· Open notepad and add the
code as above.
· Save the file as:
MyFirstJavaProgram.java.
· Open a command prompt
window and go to 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).
· Now, type ' java
MyFirstJavaProgram ' to run your program.
· You will be able to see
' Hello World ' printed on the window.
Output:
C:\> javac MyFirstJavaProgram.java
C:\> java MyFirstJavaProgram
Hello World
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