default method java code example

Example 1: default method in java

public interface SomeInterface(){
	default void test(){
    	//this will be done when the method is called by default
    }
}
public class SomeInterfaceImpl implements SomeInterface{
	//has test method from SomeInterface, can be overwritten
}
public class SomeClass{
	public void test(){
    	//do something else
    }
}
public class SomeOtherClass extends SomeClass implements SomeInterface{
	//uses the test method from SomeClass
}

Example 2: default constructor java

Default constructor is a constructor created by compiler; if user does not 
create a constructor in a class.
If user defines a constructor in a class then java compiler will not create 
default constructor.

Example 3: default constructor java

class NoteBook{
   /*This is default constructor. A constructor does
    * not have a return type and it's name
    * should exactly match with class name
    */
   NoteBook(){
      System.out.println("Default constructor");
   }
   public void mymethod()
   {
      System.out.println("Void method of the class");
   }
   public static void main(String args[]){
	/* new keyword creates the object of the class
         * and invokes constructor to initialize object
         */
	NoteBook obj = new NoteBook();
	obj.mymethod();
   }
}