依赖和关联的区别

public class Person{
	public void sayHello(){
		System.out.println("hello this is p");
	}
}

public class Demo{
	public void say(Person p){
		p.sayHello();
	}

	public static void main(String[] args){
		Demo d =new Demo();
		d.say(new Person());
	}
}

public class DemoUtil{
	public static void say(Person p){
		p.sayHello();
	}

	public static void main(String[] args){
		DemoUtil.say(new Person());
	}
}

public class DemoE{

	private Person p;

	public void setPerson(Person p){
		this.p = p;
	}

	public void say(){
		p.sayHello();
	}

	public void sayagain(){
		System.out.print("hello this is a DemoE and ");
		p.sayHello();
	}

	public static void main(String[] args){
		DemoE d =new DemoE();
		d.setPerson(new Person());
		d.say();
		d.sayagain();
	}
}