Inner Class Example

public class DataStructure {
	private static final int SIZE = 15;
	private static int[] arrayOfInts = new int[SIZE];
	
	public DataStructure() {
		for (int i = 0; i < SIZE; i++) {
			arrayOfInts[i] = i;
		}
	}
	
	public int getSIZE() {
		return SIZE;
	}
	
	public static int getValueOfArray(int index) {
		return arrayOfInts[index];
	}
		
	public void printEven() {
		InnerEvenIterator iterator = new InnerEvenIterator();
		while (iterator.hasNext(getSIZE())) {
			System.out.print(iterator.getNext() + " ");
		}
	}
	
	//Inner Class
/* 	private class InnerEvenIterator {
		private int next = 0;
		
		public boolean hasNext() {
			return (next <= SIZE - 1);
		}
		
		public int getNext() {
			int valueNext = arrayOfInts[next];
			next += 2;
			return valueNext;
		}
	} */
	
	public static void main(String[] args) {
		DataStructure ds = new DataStructure();
		ds.printEven();
	}	
}

public class InnerEvenIterator {
	private int next = 0;
	
	public boolean hasNext(int S) {
		return (next <= S - 1);
	}
	
	public int getNext() {
		int valueNext = DataStructure.getValueOfArray(next);
		next += 2;
		return valueNext;
	}
}

Các điểm giống và khác nhau khi dùng cách 1 và 2.