What is a Default Method? Why do we need Default methods in Java 8 Interfaces?

Question

Why do I need to override the equals and hashCode methods in Java? I mean Why always override hashcode() if overriding equals()?

Answer 1

Before Java 8, interfaces could have only abstract methods. The implementation of these methods has to be provided in a separate class. So, if a new method is to be added in an interface then its implementation code has to be provided in the class implementing the same interface. To overcome this issue, Java 8 has introduced the concept of default methods which allow the interfaces to have methods with implementation without affecting the classes that implement the interface.

Syntax
public interface vehicle {
default void print(){
System.out.println("I am a vehicle!");
}
}