Java

this references to itselft

public class Car
{
	private String maker;

	public Car(String maker)
	{
		this.maker = maker;
	}

	public String toString()
	{
		return "Maker: "+this.maker;
	}

	public static void main(String args[])
	{
		Car c = new Car("Buick");

		System.out.println(c);
	}
}

public class Car
{
	private String maker;

	public Car(String maker)
	{
		this.maker = maker;
	}

	public String toString()
	{
		return "Maker: "+this.maker;
	}

	public static void main(String args[])
	{
		Car [] c = new Car[10];

		for(int i = 0; i < 10; i++)
			c[i] = new Car("Buick"+i);

		for(int i = 0; i < 10; i++)
			System.out.println(c[i]);
	}
}

Inner class(or non-static nested class) can access both static and non-static members of Outer class
An instance of Inner class cannot be created without an instance of outer class and an Inner class can reference data and methods defined in Outer class in which it nests, so we don’t need to pass reference of an object to the constructor of the Inner class

public class S
{
	//non-static attribute
	private int age;

	//non-static methods
	public int getAge() {return age;}
	public void setAge(int a) {age = a;}

	//static attribute
	private static int count = 0;

	//static method
	public static int getCount() {return count;}

	//inner class
	public class D
	{
		private int year;

		public D(int y) { year = y;}

		public int getYear() { return year;}

		//acess static attribute and static method
		public String toString() { return "D: "+year+" "+count+" "+getCount();}

		public void display()
		{
			//access instance method
			System.out.println("D: "+age);
		}
	}
}

public class STest
{
	public static void main(String args[])
	{
		//create instance of S
		S c = new S();
		c.setAge(37);

		//ceate instance of D
		S.D d = c.new D(2018);

		System.out.println(d);
		d.display();
	}
}