Learn Java by Starting from First Program - Hello World
It's always exciting to write your first program and execute it without error. In this post you will learn to write your first java program.
Pre-Requisite Softwares :
1. Java SE Development Kit or JDK - It is generally a Java Software which you need to install on your system before writing any code in Java. And after installing java set Java Path in your environment variables.
Pre-Requisite Softwares :
1. Java SE Development Kit or JDK - It is generally a Java Software which you need to install on your system before writing any code in Java. And after installing java set Java Path in your environment variables.
- Download Latest Java Version from following link - Java Download
Creating Hello World Program
- Declare a class 'MyFirstProgram'
- Declare the main method public static void main()
- And print a string "Hello World" using System.out.println()
Hello World Program
// Class
class MyFirstProgram {
// Main method
public static void main(String[] args) {
// Print Hello World
System.out.println("Hello World");
}
}
Java Keywords used in 'Hello World' Program
- class keyword is used to declare a class.
- Public is an access modifier which defines main method's accessibility. Public means main method is global or accessible to all other classes in the project.
- static is a keyword in java, when static is used with any method then it is called static method. Static method can be called without creating the object of the class.
- main is the method name and also the execution point of any program. Main method is required to execute the program.
- String[] args is an array of string is basically for command line arguments.
- System.out.println() is used to print any statement.
- System is a class
- out is the object of PrintStream class
- println() is method of PrintStream class
Run the First Program:
- If you are using Eclipse then you can run this program by just clicking the green play button displayed on the top bar.
- Or right click anywhere in the class and click 'Run as Java Program'.
Output:
- Hello World - will be displayed in the console
JDK, JRE & JVM << Previous || Next >> Java Variables
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