Java First Program
Scenario 1: Program Entry Point
Imagine you are about to launch a new Java application. You write your code, but where does the program actually start running?
Interview Question
What is the meaning of 'public static void main(String[ ] args)' in Java ?
Answer:
- public - Access Modifier
- static - Reserved Keyword
- void - No value is returned after execution
- main - The program start running for compiling
- String[] args - Allows command-line input when executing the program.
Tips: Always remember that public static void main(String[] args) is the entry point of any Java application.
Scenario 2: First-Time Execution
You are just finished writing your first Java file, HelloWorld.Java, and want to see it in action.
Interview Question
What are the steps to compile and run a Java program ?
Answer:
Step - 01: Write the Java program in a .Java file (Ex- Helloworld.java).
Step - 01: Write the Java program in a .Java file (Ex- Helloworld.java).
Step - 02: Compile the program using command prompt by giving instruction.
--> javac Helloworld.java
Step - 03: Run the program using.
--> java Helloworld
Output will display.
Scenario 3: Output on Screen
You want your program to greet the user or display a result.
Interview Question
What is the purpose of 'System.out.println()' in Java?
Answer:
- System.out.println() is used to print messages to the console.
- It is a built-in Java method from the System class.
Example:
- System.out.println("Hello world!")
- Hello world! in the output will printed.