继承：在子类构造方法中调用父类的构造方法

abstract class Pet {
        private String name;
    	private String sex;

        public Pet(String name,String sex) {
            this.name = name; 
            this.sex = sex;
        }

        public String getName(){
            return name;
        }
        public String getSex(){
            return sex;
        }
        public void setName(String name){
            this.name = name;
        }
        public void setSex(String sex){
            this.sex = sex;
        }
    	    	
}
class Dog extends Pet {
    private String color;
	public Dog(String name,String sex,String color) {
    	super(name,sex);  //调用父类的构造方法
        this.color = color;
    }
}