Multilevel Inheritance in Java

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In multilevel inheritance a parent class is extended by child class and this child class is again extended by another class. Let us understand with help of a diagram:

Above diagram shows an example of multilevel inheritance. Class B extends class A and class C extends class B.

  • Here the members of class A will be accessible by the object of class C, although class C is not directly extending class A.
  • Also the members of class A can be directly used inside class C.

Let us look at the java code to understand the relationship:

public class Tech4Humans {
	public static void main(String[] args) {
		C obj = new C();
		
		//object of class C is able to access members of class A due to multilevel inheritance
		obj.var1=20;
		obj.var2=30;
		
		obj.methodA();
		obj.methodC();
		System.out.println("var1="+obj.var1);
		System.out.println("var2="+obj.var2);
	}
}

class A{
	int var1;
	
	void methodA() {
		System.out.println("method in class A");
	}
}

class B extends A{
	int var2;
	
	void methodB() {
		System.out.println("method in class B");
	}
}

class C extends B{
	int var3;
	
	void methodC() {
		System.out.println("method in class C");
		//members of class A are directly accessible inside class C due to multilevel inheritance
		System.out.println("printing variable of class A = "+var1);
		System.out.println("printing variable of class B = "+var2);
	}
}

Output

method in class A
method in class C
printing variable of class A = 20
printing variable of class B = 30
var1=20
var2=30

Let us take a look at another type of inheritance – Hierarchical inheritance.

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