How to Create Class in Java: Syntax and Example

In Java, you create a class using the class keyword followed by the class name and curly braces. Inside the class, you can define variables and methods to describe the object's properties and behaviors.

Syntax

A Java class is defined using the class keyword, followed by the class name and a pair of curly braces { }. Inside the braces, you can add variables (to store data) and methods (to perform actions).

• class: keyword to declare a class
• ClassName: the name of your class (should start with a capital letter)
• { }: curly braces to hold the class body

java

class ClassName {
    // variables and methods go here
}

Example

This example shows how to create a simple class named Car with a variable and a method. The main method creates an object of the class and calls its method.

java

class Car {
    String color; // variable to store color

    void displayColor() {
        System.out.println("Car color is " + color);
    }

    public static void main(String[] args) {
        Car myCar = new Car(); // create object
        myCar.color = "red";  // set variable
        myCar.displayColor();   // call method
    }
}

Output

Car color is red

Common Pitfalls

Common mistakes when creating classes in Java include:

• Forgetting to use the class keyword.
• Not capitalizing the class name (Java convention).
• Missing curly braces { } around the class body.
• Trying to call methods or access variables without creating an object (unless the method is static).

Here is an example of a wrong and right way:

java

// Wrong: missing class keyword and braces
// Car {
//     String color;
// }

// Right:
class Car {
    String color;
}

Quick Reference

Remember these key points when creating a class in Java:

• Use class ClassName { } to define a class.
• Class names start with a capital letter.
• Variables hold data; methods define actions.
• Create objects with new ClassName() to use non-static members.

Key Takeaways

Use the class keyword followed by a capitalized name and curly braces to create a class.

Inside the class, define variables and methods to describe data and behavior.

Create objects with new ClassName() to access non-static members.

Always include curly braces to enclose the class body.

Follow Java naming conventions for readability and best practice.