• 抽象類：傳入該抽象類的子類物件

eg：

package javaBasic;

public class TestAbstract {
	public static void main(String[] args) {
		 FreshLad fl = new FreshLad();//想調ta的方法，要先new出來ta先呀~
		 Lad l = new Fool();//間接實現抽象類
		 fl.method(l);
	}
}

abstract class Lad{
	public abstract void need();
}

class FreshLad{
	public void method(Lad l) {
		l.need();
	}
}

class Fool extends Lad{
	public void need() {
		System.out.println("memorize more words\ncet-6 come on!");
	}
}

 

• 介面：傳入該介面的實現類物件
  eg如下：

  package javaBasic;
  
  public class TestAbstract {
  	public static void main(String[] args) {
  		 /*FreshLad fl = new FreshLad();
  		 Lad l = new Fool();//間接實現抽象類
  		 fl.method(l);*/
  		FreshYouth fy = new FreshYouth();
  		Youth y = new Idiot();
  		fy.method(y);
  	}
  }
  
  interface Youth{
  	abstract void struggle();
  }
  
  class FreshYouth{
  	public void method(Youth y) {
  		y.struggle();
  	}
  }
  
  class Idiot implements Youth{
  	public void struggle() {
  		System.out.println("study grammer well\ncet-6 fighting!!");
  	}
  }