Java - 1st Java Program Explanation - Program Syntax Tutorial
// Java 1st Hello World Program
public class FirstProgram{
public static void main(String[] args) {
System.out.println("Hello World");
/* This Line will Print Hello World */
}
}
Java FirstProgram Explanation
- Every line of code must be written inside class. In our case class name is FirstProgram
- Class Should Always start with Capital letter.
- Java File name and Class name should be same. In our case file name FirstProgram.java should match with class name FirstProgram.
- Java is case-sensitive , FirstProgram and firstprogram has different meaning.
Syntax Explanation
- Class Keyword- It is used to declared a classname in java.For example in below example we use class FirstProgram{…} . So here we declare FirstProgram as a classname.
- Public keyword- It is access modifier. Which means it is publicly (visible) to all.
- Static keyword- If we declare any method as static, then it will automatically invoke by JVM. Therefore main method is automatically invoke by JVM. Because it is static method.
- void is the return type of the method. It means it doesn't return any value.
- Main Method
Every java program has main() method.Which is entry point of a program.
- String[] args
- System.out.println()
It is used to print message. As shown in example we have printed “Hello World”.Same as printf in C Programming.
How Java Program Run?
Compilation:
When we compile Java program using javac tool, java compiler converts the source code (i.e FirstProgram.java) into byte code (FirstProgram.class).