反射认识_06_ArrayList_HashSet区别

包01：

package ReflectionCollection;

public class ReflectionConstructorPoint {
	private int x;
	public int y;

	public ReflectionConstructorPoint(int x, int y) {
		super();
		this.x = x;
		this.y = y;
	}
}

　　

包02：

package ReflectionCollection;

import java.util.ArrayList;
import java.util.Collection;
import java.util.HashSet;

public class ReflectionConstructor {
	public static void main(String[] args) throws Exception {
		ReflectionConstructorPoint rcp1=new ReflectionConstructorPoint(1, 1);
		ReflectionConstructorPoint rcp2=new ReflectionConstructorPoint(2, 2);
		ReflectionConstructorPoint rcp3=new ReflectionConstructorPoint(3, 3);

		/*验证ArrayList，重复添加后大小，有序集合*/
		Collection col1=new ArrayList();
		col1.add(rcp1);
		col1.add(rcp1);//第二次添加
		col1.add(rcp2);
		col1.add(rcp3);
		System.out.println(col1.size());//结果为4

		/*验证HashSet，重复添加后大小，无序集合*/
		Collection col2=new HashSet();
		col2.add(rcp1);
		col2.add(rcp1);//第二次添加
		col2.add(rcp2);
		col2.add(rcp3);
		System.out.println(col2.size());//结果为3
	}
}