What is Java Syntax?

Java syntax refers to the set of rules and structure that define how Java code is written. Every Java application starts with a class, contains methods, statements, blocks, and expressions.

Basic Java Syntax

// This is a single line comment

/* This is a 
   multi-line comment */

/*
Every Java application starts with a class
with the main method.
*/
public class HelloWorld {

    // main method — entry point for the application
    public static void main(String[] args) {
        System.out.println("Hello, Java!");
    }
}

Explanation

public class HelloWorld:

• public = Access modifier
• class = Declares a class
• HelloWorld = Name of the class (should match file name)

public static void main(String[] args):

• public = Accessible from anywhere
• static = We can call main without instantiating the class
• void = This method doesn’t return a value
• String[] args = Command-like array of strings passed when we run the application

System.out.println("Hello, Java!");:

• Prints text to the console.

Java Statements

Variable Declaration:

int number = 10;
String message = "Hello, Java.";
double price = 99.99;
boolean isValid = true;

Control Structures

If-Else:

if (number > 5) {
    System.out.println("number is greater than 5.");
} else {
    System.out.println("number is not greater than 5.");
}

For Loop:

for (int i = 0; i < 5; i++) {
    System.out.println("Iteration: " + i);
}

While Loop:

int count = 0;

while (count < 5) {
    System.out.println("Count is: " + count);
    count++;
}

Method Definition

public static int addNumbers(int a, int b) {
    return a + b;
}

public static void main(String[] args) {
    int sum = addNumbers(5, 10);
    System.out.println("Sum = " + sum);
}

Summary

• Java is case-sensitive.
• All code belongs to a class.
• The main method is the entry point for a Java application.
• Comments aid understanding code.
• Statements typically end with a semicolon (;).