Difference between interface and class in Java

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This article, explains the difference between an interface and a class in Java.

Class

A class is a user-defined blueprint for creating objects.

The “class” keyword is used for creating classes.
A class can be instantiated, which means a class can create objects.
It does not support multiple inheritances.
A class can inherit another class.
It contains constructors.
It doesn’t contain any abstract methods.
Methods and variables in a class can be declared using any access modifiers (private, protected, public)

Class implementation in Java

# Example of class in Java
class ClassExample{
    private String name;
    ClassExample(String name){
        this.name = name;
    }
    public void display(){
        System.out.println("My name is "+name);
    }
}
public class Main
{
  public static void main(String[] args) {
    ClassExample obj1 = new ClassExample("Jonny");
    obj1.display();
  }
}

Output

My name is Jonny

Interface

The interface is a blueprint of the class. It defines what a class should do but not how.

The “interface” keyword is used for creating interfaces in Java.
An interface can’t be instantiated which means objects cannot be created.
It supports multiple inheritances.
It can’t inherit a class.
It does not contain constructors.
An interface contains only abstract methods.
All methods and variables in an interface are declared as public.

Interface implementation in Java

// Example of interface in Java
interface interfaceExample{
    static String name = "harry";
    void display();
}
// class implements interface
class TestExample implements interfaceExample{
    public void display(){
        System.out.println("Hello, "+name+" !!!");
    }
}
public class Main
{
  public static void main(String[] args) {
    TestExample test = new TestExample();
    test.display();
  }
}

Output