Java Syntax & Naming Conventions

What is Java Syntax?

Java syntax is like the grammar of the English language. Just as sentences follow rules for punctuation and word order, Java code follows specific rules for how you write instructions. If you break these rules, Java won't understand your code and will show you errors.

Syntax includes rules for:

• How to write statements and end them with semicolons
• When to use curly braces { }
• How to write comments in your code
• Proper indentation and spacing
• How to use keywords and data types

Basic Java Syntax Rules You Must Know

Java Syntax Rules in Action

Here's a program that shows all the basic syntax rules we just learned:

public class SyntaxExample {
    
    public static void main(String[] args) {
        // This is a single-line comment
        System.out.println("Learning Java Syntax!");
        
        /* This is a multi-line comment
           It can span multiple lines
           and is useful for longer explanations */
        System.out.println("Rules are important");
        
        // Every statement needs a semicolon
        int number = 42;
        
        // Braces { } group code together
        {
            System.out.println("Inside a block");
        }
        
    } // End of main method
    
} // End of class

Learning Java Syntax!
Rules are important
Inside a block

What You See:

• // Comment: Single-line comment explaining the code
• /* */ Comment: Multi-line comment for longer explanations
• Semicolons: Every statement ends with ;
• Curly Braces: Used to group the main method and create a block inside it
• Indentation: Code is indented to show structure

What Are Naming Conventions?

Naming conventions are unwritten rules that programmers follow when naming their variables, classes, methods, and other elements. They don't affect whether your code works, but they make your code professional and easy for others to understand.

Think of naming conventions like the way people name their children—you follow certain patterns. In programming, you follow patterns too, and these patterns help everyone understand your code better.

Java Naming Conventions Explained

Naming Conventions in a Real Program

Here's a complete program that follows all Java naming conventions correctly:

package com.school.students;

public class StudentInfo {
    
    // Constants use ALL_CAPS
    public static final double PI_VALUE = 3.14;
    public static final int MAX_STUDENTS = 100;
    
    // Variables use camelCase
    private String studentName;
    private int studentAge;
    private double totalMarks;
    
    // Method names use camelCase and are verbs
    public void displayStudentInfo() {
        System.out.println("Student: " + studentName);
        System.out.println("Age: " + studentAge);
    }
    
    public double calculatePercentage() {
        return (totalMarks / 100) * 100;
    }
    
    public void setStudentName(String name) {
        studentName = name;
    }
    
    public static void main(String[] args) {
        StudentInfo student = new StudentInfo();
        student.setStudentName("John");
        student.studentAge = 18;
        student.totalMarks = 85.5;
        
        student.displayStudentInfo();
        System.out.println("Percentage: " + student.calculatePercentage());
    }
}

Student: John
Age: 18
Percentage: 85.5

What We See Here:

• Package: com.school.students - all lowercase with dots
• Class: StudentInfo - PascalCase, noun (a thing)
• Constants: PI_VALUE, MAX_STUDENTS - ALL_CAPS
• Variables: studentName, studentAge - camelCase
• Methods: displayStudentInfo(), calculatePercentage() - camelCase, verbs

Pro Tips for Good Naming

• Be Descriptive: Use names that explain what something does. userName is better than un
• Avoid Single Letters: Don't use x, y, z for variables (except in loops). Use meaningful names
• Use English Words: Write your code in English so it's understandable worldwide
• Don't Use Abbreviations: calculateTotalAmount is better than calcTotAmt
• Use Real Words: Names should make sense to someone reading your code
• Avoid Numbers at the Start: Don't write 1stStudent - write firstStudent instead
• Use Pronounceable Names: Names should be easy to say out loud

Common Syntax & Naming Mistakes to Avoid

Quick Reference: Naming Conventions at a Glance

Key Takeaways

• Syntax is mandatory: Break syntax rules and your code won't run
• Naming conventions are not mandatory but professional: Follow them to write code like a pro
• End statements with semicolons (;) - this is essential
• Always balance curly braces { } - every opening brace needs a closing brace
• Java is case-sensitive: Age is different from age
• Use meaningful names: Names should describe what they represent
• Follow the pattern: Classes are PascalCase, variables and methods are camelCase
• Good code is readable code: Write code that others can understand easily